Get Operator files for testing (#1613)

.github/workflows/operator.yaml

@@ -27,6 +27,11 @@ jobs:
           node-version: '17'
       - name: Check out code into the Go module directory
         uses: actions/checkout@v2
+      - name: Check out operator as a nested repository
+        uses: actions/checkout@v2
+        with:
+          repository: minio/operator
+          path: operator
       - uses: actions/cache@v2
         with:
           path: |