add check-mocks github workflow (#263)

.github/workflows/check-mocks.yml

@@ -0,0 +1,32 @@
+name: check mocks up-to-date
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  make-mocks:
+    name: make mocks and check for diffs
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout repo
+        uses: actions/checkout@v4
+
+      - name: install go1.21
+        uses: actions/setup-go@v5
+        with:
+          go-version: "1.21"
+
+      - name: run make mocks and check for diffs
+        run: |
+          make mocks
+          if [ ! -z "$(git status --porcelain)" ]; then
+            printf "Current generated mocks not up to date\n"
+            git diff
+            git status
+            exit 1
+          fi