chore: add .tool-versions and expand CI matrix to Elixir 1.19.5 + OTP 28.4

Author: fahchen

.github/workflows/elixir.yml

@@ -21,11 +21,15 @@ jobs:
       fail-fast: false
       matrix:
         include:
+          - elixir: 1.19.5
+            otp: 28.4
+            lint: lint
+          - elixir: 1.19.5
+            otp: 27.2
           - elixir: 1.18.0
             otp: 27.2
           - elixir: 1.17.3
             otp: 27.2
-            lint: lint
     steps:
       - name: Checkout
         uses: actions/checkout@v4

.tool-versions

@@ -0,0 +1,2 @@
+erlang 28.4
+elixir 1.19.5-otp-28