Run tests on Emacs versions up to 29.2

.github/workflows/test.yml

@@ -16,15 +16,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        # See https://github.com/purcell/nix-emacs-ci/blob/master/flake.nix
         emacs_version:
+          - 29.2
+          - 28.2
           - 27.2
-          # - 27.1
           - 26.3
-          # - 26.2
-          # - 26.1
           - 25.3
-          # - 25.2
-          # - 25.1
           - 24.5
           - 24.4
           - snapshot