Add a CI job to ensure generated types are updated

Ensure that type generation from `schema.json` is up-to-date.

* Check out the repo
* Run `make generate`
* Ensure that there is no diff

.github/workflows/build.yml

@@ -57,6 +57,24 @@ jobs:
           fi
         done
 
+  type-generation:
+    name: type generation
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Generate types
+        run: |
+          make generate
+
+      - name: Ensure generated types are up-to-date
+        run: |
+          if ! git diff --quiet; then
+            echo "generated types are out of date!"
+            echo "run `make generate` to regenerate type definitions from `schema.json`"
+            exit 1
+          fi
+
   license-check:
     name: License check
     runs-on: ubuntu-latest
@@ -106,7 +124,7 @@ jobs:
 
   release:
     runs-on: ubuntu-latest
-    needs: [test, lint, examples, license-check]
+    needs: [test, lint, examples, license-check, type-generation]
     if: startsWith(github.ref, 'refs/tags/')
     env:
       DOCKER_CLI_EXPERIMENTAL: "enabled"