Add beta branch support for releases (#282)

Updated release workflow and semantic-release config to include the beta
branch and pattern-matched branches for release automation. The beta
branch is now marked as a prerelease.

.github/workflows/release.yml

@@ -3,7 +3,9 @@ name: release
 on:
   push:
     branches:
+      - "*.x"
       - main
+      - beta
 
 permissions:
   contents: write