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/upload_symbols.py b/scripts/upload_symbols.py
index 6896f8a..0038203 100644
--- a/scripts/upload_symbols.py
+++ b/scripts/upload_symbols.py
@@ -422,7 +422,7 @@
                 "debug_id": symbol.header.id.replace("-", ""),
             }
         }
-        with open(symbol.file_name, "r") as fp:
+        with open(symbol.file_name, "r", encoding="utf-8") as fp:
             logging.debug("Executing put to uploadUrl: %s", symbol.display_name)
             ExecRequest(
                 "put",
@@ -577,7 +577,7 @@
         )
 
     if failed_list is not None:
-        with open(failed_list, "w") as fl:
+        with open(failed_list, "w", encoding="utf-8") as fl:
             for s in upload_failures:
                 fl.write("%s\n" % s.display_path)