Update minimum Node.js version to v14 (#117)

The minimum Node.js version has been updated from v12 to v14, and CI
has been updated to test v18.

.github/workflows/build-lint-test.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        node-version: [12.x, 14.x, 16.x]
+        node-version: [14.x, 16.x, 18.x]
     steps:
       - uses: actions/checkout@v2
       - name: Use Node.js ${{ matrix.node-version }}
@@ -39,10 +39,12 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
-      - name: Use Node.js v12
-        uses: actions/setup-node@v2
+      - name: Get Node.js version
+        id: nvm
+        run: echo ::set-output name=NODE_VERSION::$(cat .nvmrc)
+      - uses: actions/setup-node@v2
         with:
-          node-version: 12
+          node-version: ${{ steps.nvm.outputs.NODE_VERSION }}
       - run: yarn --frozen-lockfile
       - run: yarn build
       - run: yarn setup:postinstall

.nvmrc

@@ -1 +1 @@
-v12
+v14

README.md

@@ -87,7 +87,7 @@ try {
 
 ### Setup
 
-- Install [Node.js](https://nodejs.org) version 12
+- Install [Node.js](https://nodejs.org) version 14
   - If you are using [nvm](https://github.com/creationix/nvm#installation) (recommended) running `nvm use` will automatically choose the right node version for you.
 - Install [Yarn v1](https://yarnpkg.com/en/docs/install)
 - Run `yarn setup` to install dependencies and run any requried post-install scripts

package.json

@@ -9,7 +9,7 @@
   "main": "dist/index.js",
   "bin": "dist/cli.js",
   "engines": {
-    "node": ">=12.0.0"
+    "node": ">=14.0.0"
   },
   "files": [
     "dist/"