Update node version we're using in the CI

Author: garronej

.github/workflows/ci.yaml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       matrix:
         #node: [ '16', '17' ]
-        node: [ '18' ]
+        node: [ '20' ]
         #os: [ windows-latest, ubuntu-latest ]
         os: [ ubuntu-latest ]
     name: Test with Node v${{ matrix.node }} on ${{ matrix.os }}