Update eepp-build-check.yml

Test 3 checkout submodules.

.github/workflows/eepp-build-check.yml

@@ -11,9 +11,13 @@ jobs:
       with:
         fetch-depth: 2
         ref: develop
-        shell: bash
-        run: |
-          git submodule sync --recursive
+    - uses: actions/checkout@v2
+    - name: Checkout submodules
+      shell: bash
+      run: |
+        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
     - name: Install dependencies
       run: |
         sudo apt-get update