Remove otp 28

Author: simonprev

.github/workflows/ci.yml

@@ -8,7 +8,7 @@ jobs:
 
     strategy:
       matrix:
-        otp-version: [27.2, 28.1]
+        otp-version: [27.2]
         elixir-version: [1.17, 1.18, 1.19]
 
     services: