Update react-native-code-push-ci.yml (microsoft#2608)

Author: AnatolyPristensky

.github/workflows/react-native-code-push-ci.yml

@@ -60,6 +60,8 @@ jobs:
         with:
           ruby-version: '2.7.6'
           bundler-cache: true
+      - name: (Workaround) Install activesupport 7.0.8
+        run: gem install activesupport -v 7.0.8
       - name: Install dependencies
         run: npm install
       - name: Setup iOS tests