stop testing with node 12 and 14

Author: simonhaenisch

.github/workflows/main.yml

@@ -7,7 +7,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node: [12, 14, 16, 18]
+        node: [16, 18, 20]
         os: ['ubuntu-latest', 'windows-latest', 'macOS-latest']
 
     name: Node ${{ matrix.node }} on ${{ matrix.os }}