Update Elixir version in CI workflow

Author: josevalim

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
           - elixir_version: 1.19
             otp_version: 28.1.1
             lint: true
-          - elixir_version: 1.14
+          - elixir_version: 1.16
             otp_version: 25.3.2.18
     steps:
       - uses: actions/checkout@v3