fix CI build error

This is a fix for
"Unexpected error while parsing HEAD commit: Missing commit"

Author: sullis

.github/workflows/ci.yml

@@ -16,6 +16,8 @@ jobs:
         java: [ '8' ]
     steps:
     - uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
     - name: Set up JDK ${{ matrix.java }}
       uses: actions/setup-java@v1
       with: