[ci] fix codecov upload (#3715)

Author: hannahkm

.github/workflows/unit-integration-tests.yml

@@ -279,6 +279,7 @@ jobs:
         uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
         with:
           ref: ${{ inputs.ref || github.ref }}
+          fetch-depth: $(( ${{ github.event_name == 'pull_request' && github.event.pull_request.commits || 0 }} + 1 ))
 
       - name: Setup Go
         uses: ./.github/actions/setup-go
@@ -348,6 +349,7 @@ jobs:
         uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
         with:
           ref: ${{ inputs.ref || github.ref }}
+          fetch-depth: $(( ${{ github.event_name == 'pull_request' && github.event.pull_request.commits || 0 }} + 1 ))
 
       - name: Setup Go
         uses: ./.github/actions/setup-go