ci: fix deprecated codecov argument

Author: cakebaker

.github/workflows/ci.yml

@@ -200,7 +200,7 @@ jobs:
         # if: steps.vars.outputs.HAS_CODECOV_TOKEN
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
-          file: ${{ steps.coverage.outputs.report }}
+          files: ${{ steps.coverage.outputs.report }}
           ## flags: IntegrationTests, UnitTests, ${{ steps.vars.outputs.CODECOV_FLAGS }}
           flags: ${{ steps.vars.outputs.CODECOV_FLAGS }}
           name: codecov-umbrella