goLint: add a check that go.mod is tidied

.github/workflows/goLint.yml

@@ -59,7 +59,15 @@ jobs:
         run: |
           git config --global url.https://${{ secrets.PAT }}@github.com/.insteadOf git+ssh://[email protected]
           git config --global [email protected]:.insteadOf https://github.com/
+      - name: Check that go.mod is tidied
+        run: |
+          cp go.mod go.mod.orig
+          cp go.sum go.sum.orig
+          go mod tidy
+          diff go.mod go.mod.orig
+          diff go.sum go.sum.orig
       - name: Run Linter
+        if: success() || failure() # run this step even if the previous one failed
         uses: golangci/golangci-lint-action@a4f60bb28d35aeee14e6880718e0c85ff1882e64 # v6.0.1
         with:
           version: v1.59.1