Add Elixir 1.18.x to testing matrix

Author: mneudert

.github/workflows/ci.yaml

@@ -21,7 +21,7 @@ jobs:
         id: setup
         uses: erlef/setup-beam@v1
         with:
-          elixir-version: '1.17.3'
+          elixir-version: '1.18.1'
           otp-version: '27.2'
 
       - name: mix-cache
@@ -74,7 +74,7 @@ jobs:
         id: setup
         uses: erlef/setup-beam@v1
         with:
-          elixir-version: '1.17.3'
+          elixir-version: '1.18.1'
           otp-version: '27.2'
 
       - name: mix-cache
@@ -141,6 +141,10 @@ jobs:
             otp: '27.2'
             cayley: 'v0.7.6'
             runs-on: ubuntu-24.04
+          - elixir: '1.18.1'
+            otp: '27.2'
+            cayley: 'v0.7.6'
+            runs-on: ubuntu-24.04
 
     services:
       cayley: