test newer emacs versions in CI

Author: williewillus

.github/workflows/test.yml

@@ -7,9 +7,10 @@ jobs:
     strategy:
       matrix:
         emacs_version:
-          - '25.1'
-          - '26.1'
           - '27.1'
+          - '28.1'
+          - '29.1'
+          - '30.1'
 
     steps:
     - uses: purcell/setup-emacs@master