Drop support for Elixir versions < 1.15 in CI

Author: marcelotto

.github/workflows/ci.yml

@@ -15,18 +15,15 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - pair:
-              elixir: 1.14.5
-              otp: 24.3
           - pair:
               elixir: 1.15.7
-              otp: 25.3
+              otp: 24.3
           - pair:
               elixir: 1.16.2
-              otp: 26.2
+              otp: 25.3
           - pair:
               elixir: 1.17.3
-              otp: 27.3
+              otp: 26.2
           - pair:
               elixir: 1.18.3
               otp: 27.3