ci: Bump Emacs 29.x to 3

Author: jcs090218

.github/workflows/activate.yml

@@ -19,7 +19,7 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         emacs-version:
-          - 29.2
+          - 29.3
 
     steps:
     - uses: actions/checkout@v4