Test against Emacs 29 instead of master (#255)

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.github/workflows/lint.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        emacs_version: [27, 28, "master"]
+        emacs_version: [27, 28, 29]
     steps:
       - name: Checkout
         uses: actions/checkout@v4