fix: enable longpaths support for windows test (#1485)

Author: alicejli

Diff for: synthtool/gcp/templates/java_library/.github/workflows/ci.yaml

@@ -39,6 +39,8 @@ jobs:
   windows:
     runs-on: windows-latest
     steps:
+    - name: Support longpaths
+      run: git config --system core.longpaths true
     - uses: actions/checkout@v3
     - uses: actions/setup-java@v3
       with: