Add go-tidy-check workflow

.github/workflows/test-tidy.yml

@@ -0,0 +1,43 @@
+name: Go mod tidy check
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - "**.go"
+  pull_request:
+    paths:
+      - "**.go"
+
+# Abort runs of *this* workflow, if a new commit with the same ref is pushed.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
+
+jobs:
+  gotidycheck:
+    name: Go mod tidy check
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
+
+      - name: Setup Go environment
+        uses: actions/setup-go@268d8c0ca0432bb2cf416faae41297df9d262d7f
+        with:
+          go-version: "1.19.1"
+          cache: true
+
+      - name: Get Go submodules
+        id: submods
+        shell: bash
+        run: |
+          mods=$(go list -f '{{.Dir}}' -m | xargs)
+          echo "Found mods: $mods"
+          echo "::set-output name=submods::${mods}"
+
+      - name: Go tidy check
+        uses: katexochen/go-tidy-check@45731e0013a976d5d616d79007c7ba52de6ce542
+        with:
+          modules: ${{ steps.submods.outputs.submods }}