Fix pypa/gh-action-pypi-publish version reference (#69)

The previous change incorrectly used @v1 which doesn't exist.
Pin to release/v1.13 SHA for security best practices.

Signed-off-by: Salman Muin Kayser Chishti <[email protected]>

Author: salmanmkc

.github/workflows/publish.yml

@@ -29,4 +29,4 @@ jobs:
       - name: Build package
         run: uv build
       - name: Publish to PyPI
-        uses: pypa/gh-action-pypi-publish@v1
+        uses: pypa/gh-action-pypi-publish@ed0c53931b1dc9bd32cbe73a98c7f6766f8a527e  # release/v1.13