chore: pin GitHub Actions (#39)

Co-authored-by: OpenAI Codex <codex@openai.com>

Author: jbeckwith-oai

.github/workflows/release-please.yml

@@ -78,7 +78,7 @@ jobs:
           fi
 
       - name: Upload build artifacts
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
         with:
           name: dist
           path: dist/
@@ -97,12 +97,12 @@ jobs:
       id-token: write
     steps:
       - name: Download build artifacts
-        uses: actions/download-artifact@v8
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8
         with:
           name: dist
           path: dist/
 
       - name: Publish to PyPI
-        uses: pypa/gh-action-pypi-publish@release/v1
+        uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # release/v1
         with:
           print-hash: true

.github/workflows/test.yml

@@ -239,7 +239,7 @@ jobs:
         run: uv build
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
         with:
           name: dist
           path: dist/