Add GitHub action for PR fuzzing

https://google.github.io/clusterfuzzlite/running-clusterfuzzlite/github-actions/

.github/workflows/cflite_pr.yml

@@ -0,0 +1,48 @@
+name: ClusterFuzzLite PR fuzzing
+on:
+  pull_request:
+    paths:
+      - '**'
+permissions: read-all
+jobs:
+  PR:
+    runs-on: ubuntu-latest
+    concurrency:
+      group: ${{ github.workflow }}-${{ matrix.sanitizer }}-${{ github.ref }}
+      cancel-in-progress: true
+    strategy:
+      fail-fast: false
+      matrix:
+        sanitizer:
+        - address
+        # Override this with the sanitizers you want.
+        # - undefined
+        # - memory
+    steps:
+    - name: Build Fuzzers (${{ matrix.sanitizer }})
+      id: build
+      uses: google/clusterfuzzlite/actions/build_fuzzers@v1
+      with:
+        language: c++
+        github-token: ${{ secrets.GITHUB_TOKEN }}
+        sanitizer: ${{ matrix.sanitizer }}
+        # Optional but recommended: used to only run fuzzers that are affected
+        # by the PR.
+        # See later section on "Git repo for storage".
+        # storage-repo: https://${{ secrets.PERSONAL_ACCESS_TOKEN }}@github.com/OWNER/STORAGE-REPO-NAME.git
+        # storage-repo-branch: main   # Optional. Defaults to "main"
+        # storage-repo-branch-coverage: gh-pages  # Optional. Defaults to "gh-pages".
+    - name: Run Fuzzers (${{ matrix.sanitizer }})
+      id: run
+      uses: google/clusterfuzzlite/actions/run_fuzzers@v1
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}
+        fuzz-seconds: 600
+        mode: 'code-change'
+        sanitizer: ${{ matrix.sanitizer }}
+        # Optional but recommended: used to download the corpus produced by
+        # batch fuzzing.
+        # See later section on "Git repo for storage".
+        # storage-repo: https://${{ secrets.PERSONAL_ACCESS_TOKEN }}@github.com/OWNER/STORAGE-REPO-NAME.git
+        # storage-repo-branch: main   # Optional. Defaults to "main"
+        # storage-repo-branch-coverage: gh-pages  # Optional. Defaults to "gh-pages".