Bump azure/setup-kubectl from 1 to 3 in /.github/workflows (#301)

Bumps [azure/setup-kubectl](https://github.com/azure/setup-kubectl) from 1 to 3 ([Release notes](https://github.com/azure/setup-kubectl/releases))

.github/workflows/ci.yaml

@@ -17,7 +17,7 @@ jobs:
         with:
           version: 'v3.7.0'
         id: install
-      - uses: azure/setup-kubectl@v1
+      - uses: azure/setup-kubectl@v3
         id: install-kubectl
       - uses: actions/checkout@v2
         with: