release: remove pip cache usage (#1025)

Author: woodruffw

.github/workflows/release.yml

@@ -21,9 +21,9 @@ jobs:
 
       - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d # v5.1.0
         with:
+          # NOTE: We intentionally don't use a cache in the release step,
+          # to reduce the risk of cache poisoning.
           python-version: "3.x"
-          cache: "pip"
-          cache-dependency-path: pyproject.toml
 
       - name: deps
         run: python -m pip install -U build