Drop pnpm cache from the release workflow - not reachable on this runner

actions/setup-node's cache: pnpm option tries to hit this Gitea
instance's Actions cache service, which times out (ETIMEDOUT against
an internal address) rather than failing fast - burning ~5 minutes on
every run before falling back to an uncached install anyway. Not
worth it for a release workflow that runs once per tag.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitea/workflows/release.yaml

@@ -18,7 +18,6 @@ jobs:
       - uses: https://github.com/actions/setup-node@v4
         with:
           node-version: 22
-          cache: pnpm
           registry-url: https://dev.pivoine.art/api/packages/valknar/npm/
 
       - run: pnpm install --frozen-lockfile