CI: pin actions by SHA

This eliminates the possibility of a tag being changed under
us.

Author: tacaswell

.github/workflows/test_and_deploy.yml

@@ -99,4 +99,4 @@ jobs:
           python -m build .
 
       - name: Publish package
-        uses: pypa/gh-action-pypi-publish@release/v1
+        uses: pypa/gh-action-pypi-publish@76f52bc884231f62b9a034ebfe128415bbaabdfc # v1.12.4