Add cifuzz CI config for OSS-Fuzz

.github/workflows/cifuzz.yml

@@ -0,0 +1,35 @@
+name: CIFuzz
+on: [pull_request]
+permissions: {}
+jobs:
+  Fuzzing:
+    runs-on: ubuntu-latest
+    permissions:
+      security-events: write
+    steps:
+    - name: Build Fuzzers
+      id: build
+      uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
+      with:
+        oss-fuzz-project-name: Cirq
+        language: python
+    - name: Run Fuzzers
+      uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
+      with:
+        oss-fuzz-project-name: Cirq
+        language: python
+        fuzz-seconds: 600
+        output-sarif: true
+    - name: Upload Crash
+      uses: actions/upload-artifact@v4
+      if: failure() && steps.build.outcome == 'success'
+      with:
+        name: artifacts
+        path: ./out/artifacts
+    - name: Upload Sarif
+      if: always() && steps.build.outcome == 'success'
+      uses: github/codeql-action/upload-sarif@v2
+      with:
+        # Path to SARIF file relative to the root of the repository
+        sarif_file: cifuzz-sarif/results.sarif
+        checkout_path: cifuzz-sarif