chore: introduce black for code format in github actions (#47)

* use black with SHA1

.github/workflows/black.yml

@@ -0,0 +1,17 @@
+name: "Black Code Formatter"
+
+on:
+  push:
+    branches:
+      - 'release-*'
+  pull_request:
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: psf/black@3702ba224ecffbcec30af640c149f231d90aebdb
+        with:
+          options: "--check --diff --line-length 100"
+          src: "hugegraph-llm/src hugegraph-python-client/src"