Merge pull request #2967 from lucas-clemente/improve-go-mod-tidy-workflow

improve go mod tidy workflow

.github/workflows/lint.yml

@@ -4,7 +4,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - run: go install ./...
+      - uses: actions/setup-go@v2
+        with:
+          go-version: "1.15.x"
       - name: Check that no non-test files import Ginkgo or Gomega
         run: .github/workflows/no_ginkgo.sh
       - name: Check that go.mod is tidied
@@ -12,8 +14,8 @@ jobs:
           cp go.mod go.mod.orig
           cp go.sum go.sum.orig
           go mod tidy
-          cmp go.mod go.mod.orig
-          cmp go.sum go.sum.orig
+          diff go.mod go.mod.orig
+          diff go.sum go.sum.orig
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v2
         with: