ci: re-add gofmt linter

.gitlab/ci/lint.gitlab-ci.yml

@@ -2,13 +2,6 @@ lint:
   image: registry.gitlab.com/gitlab-org/gitlab-build-images:golangci-lint-alpine
   stage: test
   script:
-    - FMT_CMD="gofmt -w ."
-    - eval "$FMT_CMD"
-    - |
-      if ! git diff --ignore-submodules=dirty --exit-code; then
-        echo "Some files are not formatted. Please format with \`$FMT_CMD\`"
-        exit 1;
-      fi
     - golangci-lint --version
     # Use default .golangci.yml file from the image if one is not present in the project root.
     - '[ -e .golangci.yml ] || cp /golangci/.golangci.yml .'

.golangci.yml

@@ -2,6 +2,7 @@ linters:
     enable:
         - errcheck
         - gosimple
+        - gofmt
         - govet
         - ineffassign
         - staticcheck