increase checkout depth for codecov.io

Author: mr-c

.github/workflows/ci-tests.yml

@@ -28,6 +28,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
 
       - name: Set up Singularity
         if: ${{ matrix.step == 'unit' || matrix.step == 'mypy' }}