Checkout code for codecov upload (#6849)

Having the repository available for the coverage upload action appears
to be required for the action to correctly send information about the
file structure and have successful reports.

Resolves #6564

Author: MrAlias

.github/workflows/ci.yml

@@ -120,6 +120,8 @@ jobs:
     runs-on: ubuntu-latest
     needs: [test-coverage]
     steps:
+      - name: Checkout Repo
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
         with:
           pattern: coverage-artifacts-${{ env.DEFAULT_GO_VERSION }}