fix: use macos-15 runner for x86_64 build (macos-13 retired)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: vicnaum

.github/workflows/release.yml

@@ -20,7 +20,7 @@ jobs:
             os: macos-latest
             name: shinode-macos-arm64
           - target: x86_64-apple-darwin
-            os: macos-13
+            os: macos-15
             name: shinode-macos-x86_64
 
     runs-on: ${{ matrix.os }}