Change minimum versions of Node and eslint in integration tests

Node v16 is out of support. So we test against Node v18 and v20.

eslint 7 was released 4 years ago so its fair to not actively test again
eslint 6. Speculativiely adding eslint 9 tests but not sure if that will
work

.github/workflows/node.js.yml

@@ -16,7 +16,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [12.x, 14.x, 16.x]
+        node-version: [18.x, 20.x]
         # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
 
     steps:
@@ -29,7 +29,7 @@ jobs:
     - run: npm ci
     - run: npm run lint
     - run: npm run test
-    - run: npm run integration test 6 7 8 # eslint versions
+    - run: npm run integration test 7 8 9 # eslint versions
     - name: Upload coverage to Codecov
       uses: codecov/codecov-action@v2
       with: