add semver checks to CI

Author: kurtlawrence

.github/workflows/test.yml

@@ -48,3 +48,10 @@ jobs:
           toolchain: ${{ matrix.version }}
       - name: Run tests
         run: cargo test
+  check-semver:
+    name: Check semver compatibility
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check semver
+        uses: obi1kenobi/cargo-semver-checks-action@v2
+