ci: fix arguments to npm test, add node 20

Author: isaacs

.github/workflows/ci.yml

@@ -6,7 +6,7 @@ jobs:
   build:
     strategy:
       matrix:
-        node-version: [16.x, 18.x]
+        node-version: [16.x, 18.x, 20.x]
         platform:
         - os: ubuntu-latest
           shell: bash
@@ -37,4 +37,4 @@ jobs:
         run: npm ci
 
       - name: Run Tests
-        run: npm test -- -c -t0 --statements=80 --branches=80 --functions=80 --lines=80
+        run: npm test -- -c -t0