Don't set XDG_CACHE_HOME in release.yml (#1461)

.github/workflows/release.yml

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index ef2be98..9dc1e87 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -26,9 +26,6 @@
           distribution: "zulu"
           java-version: "11"
       - name: Prepare release notes and artifacts
-        env:
-          # Bazelisk will download bazel to here.
-          XDG_CACHE_HOME: ~/.cache/bazel-repo
         run: .github/workflows/release_prep.sh ${{ env.GITHUB_REF_NAME }}
       - name: Release
         uses: softprops/action-gh-release@v1