Use a gemfile for pronto action

Author: rmosolgo

.github/workflows/pronto.yaml

@@ -4,18 +4,19 @@ on:
 
 jobs:
   pronto:
-
     runs-on: ubuntu-latest
-
     steps:
+      - run: echo BUNDLE_GEMFILE=gemfiles/pronto.gemfile > $GITHUB_ENV
       - name: Checkout code
         uses: actions/checkout@v2
       - run: git fetch --no-tags --prune --unshallow origin +refs/heads/*:refs/remotes/origin/*
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: 3.4
-      - name: Setup pronto
-        run: gem install undercover pronto pronto-rubocop pronto-undercover
+          bundler-cache: true
       - name: Run Pronto
-        run: PRONTO_PULL_REQUEST_ID="${{ github.event.pull_request.number }}" PRONTO_GITHUB_ACCESS_TOKEN="${{ github.token }}" pronto run -f github_pr -c origin/${{ github.base_ref }}
+        run: bundle exec pronto run -f github_pr -c origin/${{ github.base_ref }}
+        env:
+          PRONTO_PULL_REQUEST_ID: ${{ github.event.pull_request.number }}
+          PRONTO_GITHUB_ACCESS_TOKEN: "${{ github.token }}"

gemfiles/pronto.gemfile

@@ -0,0 +1,6 @@
+source "https://rubygems.org"
+
+gem "pronto"
+gem "pronto-rubocop"
+gem "pronto-undercover"
+gem "base64"