update ci/cd scripts

Author: kbarbounakis

.github/workflows/npmpublish.yml

@@ -11,7 +11,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-node@v2
         with:
-          node-version: 16
+          node-version: 20
       - run: npm ci
       - run: npm run ci-sub-modules --if-present
       - run: npm test

.github/workflows/npmtest.yml

@@ -9,7 +9,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [16.x, 18.x, 20.x]
+        node-version: [18.x, 20.x]
 
     steps:
     - uses: actions/checkout@v2