Add bc check

Author: jaapio

.github/workflows/push.yml

@@ -194,3 +194,20 @@ jobs:
         uses: docker://mickaelandrieu/psalm-ga
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  bc_check:
+    name: BC Check
+    runs-on: ubuntu-latest
+    needs: [setup, phpunit]
+    steps:
+      - uses: actions/checkout@master
+      - name: Restore/cache vendor folder
+        uses: actions/cache@v1
+        with:
+          path: vendor
+          key: all-build-${{ hashFiles('**/composer.lock') }}
+          restore-keys: |
+            all-build-${{ hashFiles('**/composer.lock') }}
+            all-build-
+      - name: Roave BC Check
+        uses: docker://nyholm/roave-bc-check-ga