ci: add node v18.x

Author: mscdex

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node-version: [10.x, 12.x, 14.x, 16.x]
+        node-version: [10.x, 12.x, 14.x, 16.x, 18.x]
     steps:
       - uses: actions/checkout@v2
       - name: Use Node.js ${{ matrix.node-version }}
@@ -27,7 +27,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node-version: [10.x, 12.x, 14.x, 16.x]
+        node-version: [10.x, 12.x, 14.x, 16.x, 18.x]
     steps:
       - uses: actions/checkout@v2
       - name: Use Node.js ${{ matrix.node-version }}
@@ -43,7 +43,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node-version: [10.x, 12.x, 14.x, 16.x]
+        node-version: [10.x, 12.x, 14.x, 16.x, 18.x]
     steps:
       - uses: actions/checkout@v2
       - name: Use Node.js ${{ matrix.node-version }}