ci: exclude 1.12 from OTP 25 matrix

Author: bitwalker

.github/workflows/elixir.yml

@@ -11,6 +11,9 @@ jobs:
       matrix:
         otp: ['23.3', '24.2', '25.0']
         elixir: ['1.12.3', '1.13.3', '1.14.0']
+        exclude:
+        - otp: '25.0'
+          elixir: '1.12.3'
     steps:
       - uses: actions/checkout@v2
       - uses: erlef/setup-elixir@v1