CI: update node 12 -> 14

Author: milahu

.github/workflows/build.yml

@@ -13,7 +13,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [12.x, 14.x, 16.x, 17.x]
+        node-version: [14.x, 16.x, 17.x]
 
     steps:
       - name: Checkout

.github/workflows/publish.yml

@@ -13,10 +13,10 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v2
 
-      - name: Setup Node.js 12.x to publish to npmjs.org
+      - name: Setup Node.js 14.x to publish to npmjs.org
         uses: actions/setup-node@v1
         with:
-          node-version: '12.x'
+          node-version: '14.x'
           registry-url: 'https://registry.npmjs.org'
 
       - name: Install Packages