ci: update matrix of node versions to test against (#361)

Author: G-Rath

.github/workflows/validate.yml

@@ -23,12 +23,10 @@ jobs:
       fail-fast: false
       matrix:
         eslint: [6.8.0, 6, 7.0.0, 7, 8.0.0, 8]
-        node: [12.22.0, 12, 14.17.0, 14, 16.0.0, 16]
+        node: [12.x, 14.x, 16.x, 18.x, 20.x, 21.x]
         testing-library-dom: [8, 9]
         exclude:
-          - node: 12.22.0
-            testing-library-dom: 9
-          - node: 12
+          - node: 12.x
             testing-library-dom: 9
     runs-on: ubuntu-latest
     steps: