workflows: Update branch names

Also remove main-brancy-sync workflow that was removed from the main branch.
diff --git a/.github/workflows/clang-tests.yml b/.github/workflows/clang-tests.yml
index f8ca65e..af0b5ea 100644
--- a/.github/workflows/clang-tests.yml
+++ b/.github/workflows/clang-tests.yml
@@ -28,16 +28,16 @@
     steps:
     - name: Setup Windows
       if: startsWith(matrix.os, 'windows')
-      uses: llvm/actions/setup-windows@master
+      uses: llvm/actions/setup-windows@main
       with:
         arch: amd64
     - name: Install Ninja
-      uses: llvm/actions/install-ninja@master
+      uses: llvm/actions/install-ninja@main
     - uses: actions/checkout@v1
       with:
         fetch-depth: 1
     - name: Test clang
-      uses: llvm/actions/build-test-llvm-project@master
+      uses: llvm/actions/build-test-llvm-project@main
       with:
         cmake_args: -G Ninja  -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE=Release
         build_target: check-clang
diff --git a/.github/workflows/libclc-tests.yml b/.github/workflows/libclc-tests.yml
index 4e8639b..2f1eb29 100644
--- a/.github/workflows/libclc-tests.yml
+++ b/.github/workflows/libclc-tests.yml
@@ -31,16 +31,16 @@
     steps:
     - name: Setup Windows
       if: startsWith(matrix.os, 'windows')
-      uses: llvm/actions/setup-windows@master
+      uses: llvm/actions/setup-windows@main
       with:
         arch: amd64
     - name: Install Ninja
-      uses: llvm/actions/install-ninja@master
+      uses: llvm/actions/install-ninja@main
     - uses: actions/checkout@v1
       with:
         fetch-depth: 1
     - name: Build clang
-      uses: llvm/actions/build-test-llvm-project@master
+      uses: llvm/actions/build-test-llvm-project@main
       with:
         cmake_args: -G Ninja  -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE=Release
         build_target: ""
diff --git a/.github/workflows/lld-tests.yml b/.github/workflows/lld-tests.yml
index 9b4cbe9..bdf0c2f 100644
--- a/.github/workflows/lld-tests.yml
+++ b/.github/workflows/lld-tests.yml
@@ -28,16 +28,16 @@
     steps:
     - name: Setup Windows
       if: startsWith(matrix.os, 'windows')
-      uses: llvm/actions/setup-windows@master
+      uses: llvm/actions/setup-windows@main
       with:
         arch: amd64
     - name: Install Ninja
-      uses: llvm/actions/install-ninja@master
+      uses: llvm/actions/install-ninja@main
     - uses: actions/checkout@v1
       with:
         fetch-depth: 1
     - name: Test lld
-      uses: llvm/actions/build-test-llvm-project@master
+      uses: llvm/actions/build-test-llvm-project@main
       with:
         cmake_args: -G Ninja  -DLLVM_ENABLE_PROJECTS="lld" -DCMAKE_BUILD_TYPE=Release
         build_target: check-lld
diff --git a/.github/workflows/lldb-tests.yml b/.github/workflows/lldb-tests.yml
index 229e6de..93fddc2 100644
--- a/.github/workflows/lldb-tests.yml
+++ b/.github/workflows/lldb-tests.yml
@@ -31,16 +31,16 @@
     steps:
     - name: Setup Windows
       if: startsWith(matrix.os, 'windows')
-      uses: llvm/actions/setup-windows@master
+      uses: llvm/actions/setup-windows@main
       with:
         arch: amd64
     - name: Install Ninja
-      uses: llvm/actions/install-ninja@master
+      uses: llvm/actions/install-ninja@main
     - uses: actions/checkout@v1
       with:
         fetch-depth: 1
     - name: Build lldb
-      uses: llvm/actions/build-test-llvm-project@master
+      uses: llvm/actions/build-test-llvm-project@main
       with:
         # Mac OS requries that libcxx is enabled for lldb tests, so we need  to disable them.
         cmake_args: -G Ninja  -DLLVM_ENABLE_PROJECTS="clang;lldb" -DCMAKE_BUILD_TYPE=Release -DLLDB_INCLUDE_TESTS=OFF
diff --git a/.github/workflows/llvm-tests.yml b/.github/workflows/llvm-tests.yml
index 67f318a..6753834 100644
--- a/.github/workflows/llvm-tests.yml
+++ b/.github/workflows/llvm-tests.yml
@@ -29,16 +29,16 @@
     steps:
     - name: Setup Windows
       if: startsWith(matrix.os, 'windows')
-      uses: llvm/actions/setup-windows@master
+      uses: llvm/actions/setup-windows@main
       with:
         arch: amd64
     - name: Install Ninja
-      uses: llvm/actions/install-ninja@master
+      uses: llvm/actions/install-ninja@main
     - uses: actions/checkout@v1
       with:
         fetch-depth: 1
     - name: Test llvm
-      uses: llvm/actions/build-test-llvm-project@master
+      uses: llvm/actions/build-test-llvm-project@main
       with:
         cmake_args: -G Ninja -DCMAKE_BUILD_TYPE=Release
 
@@ -60,7 +60,7 @@
             repo: ${{ github.repository }}
     steps:
     - name: Install Ninja
-      uses: llvm/actions/install-ninja@master
+      uses: llvm/actions/install-ninja@main
     - name: Install abi-compliance-checker
       run: |
         sudo apt-get install abi-dumper autoconf pkg-config
@@ -72,7 +72,7 @@
         ./configure
         sudo make install
     - name: Download source code
-      uses: llvm/actions/get-llvm-project-src@master
+      uses: llvm/actions/get-llvm-project-src@main
       with:
         ref: ${{ matrix.ref }}
         repo: ${{ matrix.repo }}
diff --git a/.github/workflows/main-branch-sync.yml b/.github/workflows/main-branch-sync.yml
deleted file mode 100644
index 5ea360e..0000000
--- a/.github/workflows/main-branch-sync.yml
+++ /dev/null
@@ -1,25 +0,0 @@
-name: main branch sync
-
-on:
-  push:
-    branches:
-      - 'main'
-
-jobs:
-  branch_sync:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout Code
-        uses: actions/checkout@v2
-        with:
-          # persist-credentials: false allows us to use our own credentials for
-          # pushing to the repository.  Otherwise, the default github actions token
-          # is used.
-          persist-credentials: false
-          fetch-depth: 0
-
-      - name: Update branch
-        env:
-          LLVMBOT_TOKEN: ${{ secrets.LLVMBOT_MAIN_SYNC }}
-        run: |
-          git push https://$LLVMBOT_TOKEN@github.com/${{ github.repository }} HEAD:master