ci: Fix Java setup for deployment to npm (shaka-project#8968)

Author: joeyparrish

.github/workflows/release-please.yaml

@@ -70,6 +70,11 @@ jobs:
           node-version: 22
           registry-url: 'https://registry.npmjs.org'
 
+      - uses: actions/setup-java@v4
+        with:
+          distribution: zulu
+          java-version: 21
+
       - name: Compute NPM tags
         run: |
           # NPM publish always sets a tag.  If you don't provide an explicit