Bump node version to 18.x (#26)

Author: sameerank

.github/workflows/publish.yml

@@ -10,7 +10,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
-          node-version: 12
+          node-version: '18.x'
       - run: yarn install
       - run: yarn test
       - uses: JS-DevTools/npm-publish@v1