Upgrade to node 20

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
     - name: Install Node.js
       uses: actions/setup-node@v3
       with:
-        node-version: '16'
+        node-version: '20'
     - name: Install dependencies
       run: npm ci
     - name: Run linter

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
     - name: Install Node.js
       uses: actions/setup-node@v3
       with:
-        node-version: '16'
+        node-version: '20'
     - name: Set up release environment
       run: |
         echo RELEASE_VERSION=${{ github.event.inputs.release-version }} >> $GITHUB_ENV

.nvmrc

@@ -1 +1 @@
-v16.20.2
+v20.11.1

CONTRIBUTING.adoc

@@ -49,7 +49,7 @@ If the command doesn't report an {url-nodejs-releases}[active LTS version] of No
 We strongly recommend that you use {url-nvm}[nvm] (Node Version Manager) to manage your Node.js installation(s).
 Follow the {url-nvm-install}[nvm installation instructions] to set up nvm on your machine.
 
-Once you've installed nvm, open a new terminal and install Node.js 16 using the following command:
+Once you've installed nvm, open a new terminal and install Node.js 20 using the following command:
 
 [,console]
 ----

README.adoc

@@ -23,7 +23,7 @@ NOTE: This extension will slightly increase build times since `.adoc` files are
 
 
 == Prerequisites
-In order to use this extension, you must be using Node.js 16 and {url-antora-docs}[Antora 3.1.0].
+In order to use this extension, you must be using Node.js 20 and {url-antora-docs}[Antora 3.1.0].
 The following instructions assume you've already set up an Antora playbook file (i.e., _antora-playbook.yml_) to build your site.
 
 To learn about using extensions with Antora, see the {url-extension-docs}[Antora extension documentation].

package.json

@@ -18,7 +18,7 @@
     "version": "node npm/version.js"
   },
   "engines": {
-    "node": ">=16.0.0"
+    "node": ">=20.0.0"
   },
   "devDependencies": {
     "eslint": "~8.27",

packages/antora-xref-extension/package.json

@@ -26,7 +26,7 @@
         "lib"
     ],
     "engines": {
-        "node": ">=16.0.0"
+        "node": ">=20.0.0"
     },
     "dependencies": {},
     "devDependencies": {},

packages/antora-xref-test-harness/package.json

@@ -8,7 +8,7 @@
     "./mocha-ci-reporter": "./lib/mocha-ci-reporter.js"
   },
   "engines": {
-    "node": ">=16.0.0"
+    "node": ">=20.0.0"
   },
   "devDependencies": {
     "chai": "~4.3",