Avoid running bundle install twice.

Author: dblock

.github/workflows/danger.yml

@@ -4,20 +4,19 @@ on: [pull_request]
 jobs:
   danger:
     runs-on: ubuntu-latest
+    env:
+      BUNDLE_GEMFILE: Gemfile.danger
     steps:
     - uses: actions/checkout@v2
       with:
         fetch-depth: 0
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 2.6
+        ruby-version: 2.7
         bundler-cache: true
     - name: Run Danger
-      env:
-        BUNDLE_GEMFILE: Gemfile.danger
       run: |
-        bundle install
         # the personal token is public, this is ok, base64 encode to avoid tripping Github
         TOKEN=$(echo -n Z2hwX0xNQ3VmanBFeTBvYkZVTWh6NVNqVFFBOEUxU25abzBqRUVuaAo= | base64 --decode)
         DANGER_GITHUB_API_TOKEN=$TOKEN bundle exec danger --verbose