ci: remove yarn cache from canary job to fix post-step path error

The cache: yarn option in setup-node causes a post-job failure when the
cache directory path doesn't match expectations. Removing it eliminates
the spurious error without affecting publish correctness.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: sserrata

.github/workflows/release.yaml

@@ -58,7 +58,6 @@ jobs:
         with:
           node-version: "22"
           registry-url: "https://registry.npmjs.org"
-          cache: yarn
       - name: Prepare git
         if: steps.packages_changed.outputs.changed == 'true'
         run: |