Update and cleanup github actions.

Author: rajiv

.github/workflows/publish.yml

@@ -8,16 +8,16 @@ jobs:
   test-bot:
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [macos-latest]
     runs-on: ${{ matrix.os }}
     steps:
       - name: Set up Homebrew
         id: set-up-homebrew
-        uses: Homebrew/actions/setup-homebrew@master
+        uses: Homebrew/actions/setup-homebrew@main
 
       - name: Cache Homebrew Bundler RubyGems
         id: cache
-        uses: actions/cache@v1
+        uses: actions/cache@v3
         with:
           path: ${{ steps.set-up-homebrew.outputs.gems-path }}
           key: ${{ runner.os }}-rubygems-${{ steps.set-up-homebrew.outputs.gems-hash }}