Run tests under newly-released Bazel 5.

See https://github.com/bazelbuild/bazel/releases/tag/5.0.0.

.github/workflows/bazel-test.yaml

@@ -1,4 +1,4 @@
-# Copyright 2021 Google LLC
+# Copyright 2021, 2022 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -26,7 +26,7 @@ jobs:
       matrix:
         # We don’t use the GitHub matrix support for the Emacs toolchain to
         # allow Bazel to cache intermediate results between the test runs.
-        bazel: [4.2.0, 4.2.1, 4.2.2, latest, rolling]
+        bazel: [4.2.0, 4.2.1, 4.2.2, 5.0.0, latest, rolling]
         os: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{matrix.os}}
     steps: