feat: supporting node 18, dropping node 12 (#295)

* feat: supporting node 18, dropping node 12

* fix: upgrading @readme/variable to support node 18

Author: erunion

.github/workflows/ci.yml

@@ -9,20 +9,25 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [14.x, 16.x]
+        node:
+          - 14
+          - 16
+          - 18
         react: [16, 17]
 
-    name: build (${{ matrix.node-version }} w/ React ${{ matrix.react }}
+    name: build (${{ matrix.node }} w/ React ${{ matrix.react }}
 
     steps:
     - uses: actions/checkout@v3
 
-    - name: Use Node.js ${{ matrix.node-version }}
+    - name: Use Node.js ${{ matrix.node }}
       uses: actions/setup-node@v3
       with:
-        node-version: ${{ matrix.node-version }}
+        node-version: ${{ matrix.node }}
 
+    # Node 14 still ships with npm@6 which doesn't install peerDeps by default.
     - name: Install npm@7
+      if: matrix.node == '14'
       run: npm install -g npm@7
 
     - name: Install dependencies

package-lock.json

@@ -11,7 +11,7 @@
   },
   "homepage": "https://readmeio.github.io/syntax-highlighter/",
   "engines": {
-    "node": "^14 || ^16"
+    "node": ">=14"
   },
   "scripts": {
     "build": "webpack --progress",