[GithubActions] Simplify checkout action (#629)

Checkout action introduced number of improvements simplifying checkout of submodules and fetch of all history for all tags and branches:
- actions/checkout#258
- actions/checkout#173

.github/workflows/gradle.yml

@@ -20,16 +20,11 @@ jobs:
     runs-on: ${{ matrix.platform }}
 
     steps:
-    - uses: actions/checkout@v2
     - name: Checkout (including submodules and tags)
-      shell: bash
-      # Fetch all history for all tags and branches: https://github.com/actions/checkout#fetch-all-history-for-all-tags-and-branches
-      # Checkout submodules: https://github.com/actions/checkout#checkout-submodules
-      run: |
-        git fetch --prune --unshallow
-        auth_header="$(git config --local --get http.https://github.com/.extraheader)"
-        git submodule sync --recursive
-        git -c "http.extraheader=$auth_header" -c protocol.version=2 submodule update --init --force --recursive --depth=1
+      uses: actions/checkout@v2
+      with:
+        submodules: recursive
+        fetch-depth: 0
 
     - name: Cache ~/.gradle/caches
       uses: actions/cache@v2