CI: remove header hacks when checking out submodules (#995)

.github/workflows/test.yaml

@@ -14,9 +14,7 @@ jobs:
     - uses: actions/checkout@v2
     - name: Checkout submodules
       run: |
-        auth_header="$(git config --local --get http.https://github.com/.extraheader)"
+        git submodule update --init
-        git submodule sync --recursive
-        git -c "http.extraheader=$auth_header" -c protocol.version=2 submodule update --init --force --recursive --depth=1
     - run: |
         docker build -t tmppilot -f Dockerfile.openpilot .
         docker save tmppilot:latest | gzip > tmppilot.tar.gz