Add release-snapshot to CI matrix

Author: purcell

.github/workflows/test.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
-        emacs_version: [23.4, 24.1, 24.2, 24.3, 24.4, 24.5, 25.1, 25.2, 25.3, 26.1, 26.2, 26.3, 27.1, 27.2, 28.1, 28.2, snapshot]
+        emacs_version: [23.4, 24.1, 24.2, 24.3, 24.4, 24.5, 25.1, 25.2, 25.3, 26.1, 26.2, 26.3, 27.1, 27.2, 28.1, 28.2, release-snapshot, snapshot]
         exclude:
           - os: macos-latest
             emacs_version: 23.4