scripts: update open calls to use explicit encoding

BUG=b:187789896
TEST=`cros lint` is clean here

Change-Id: Ia54475869c17292505537334362cd4cff6438b14
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4290041
Commit-Queue: Cindy Lin <xcl@google.com>
Reviewed-by: Cindy Lin <xcl@google.com>
Tested-by: Mike Frysinger <vapier@chromium.org>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/build_api.py b/scripts/build_api.py
index 70e8a4e..53bfc44 100644
--- a/scripts/build_api.py
+++ b/scripts/build_api.py
@@ -173,7 +173,9 @@
         namespaces.ReExecuteWithNamespace(sys.argv, preserve_env=True)
 
     # We currently don't have any APIs that want to access stdin, so rebind.
-    sys.stdin = open(os.devnull, "r")  # pylint: disable=consider-using-with
+    # pylint: disable=consider-using-with
+    sys.stdin = open(os.devnull, "r", encoding="utf-8")
+    # pylint: enable=consider-using-with
     os.dup2(sys.stdin.fileno(), 0)
 
     if opts.config.log_path: