chore: also test ESLint v7 on Node v18 (#364)

Author: MichaelDeBoey

.github/workflows/CI.yml

@@ -7,10 +7,7 @@ jobs:
     strategy:
       matrix:
         eslint: [7, 8]
-        node: [12.22.0, 12, 14.17.0, 14, 16]
-        include:
-          - eslint: 8
-            node: 18
+        node: [12.22.0, 12, 14.17.0, 14, 16, 18]
     runs-on: ubuntu-latest
     steps:
       - name: 🛑 Cancel Previous Runs