ci: update matrix, take two

Author: bitwalker

.github/workflows/elixir.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       matrix:
         otp: ['26', 'latest']
-        elixir: ['1.17', '1.18', 'latest']
+        elixir: ['1.18', 'latest']
     steps:
       - uses: actions/checkout@v4
       - uses: erlef/setup-beam@v1