CI: use standard Github Action templates

A lot of our repositories have diverged from our intended template, so this copies a templated version over whatever was here before

Connects pelias/pelias#951

.github/workflows/_test.yml

@@ -16,5 +16,6 @@ jobs:
           node-version: '${{ matrix.node-version }}'
       - name: Run unit tests
         run: |
+          [[ -f ./bin/ci-setup ]] && ./bin/ci-setup
           npm install
           npm run ci

.github/workflows/push.yml

@@ -12,7 +12,7 @@ jobs:
       - name: Install Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: Run semantic-release
         env:
           GH_TOKEN: ${{ secrets.GH_SEMANTIC_RELEASE_TOKEN }}