Add support for Node.js version 20

v20 is the current version, with scheduled end-of-life 2026-04-30¹.

The associated npm version (as of node v20.3.0) is still npm v9².

¹ https://github.com/nodejs/release#release-schedule
² https://nodejs.org/dist/index.json

.github/workflows/ci.yaml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [16, 18]
+        node: [16, 18, 20]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
@@ -26,7 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [16, 18]
+        node: [16, 18, 20]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
@@ -43,7 +43,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [16, 18]
+        node: [16, 18, 20]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
@@ -57,7 +57,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [16, 18]
+        node: [16, 18, 20]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3

package.json

@@ -7,7 +7,7 @@
   "repository": "github:nextstrain/auspice",
   "homepage": "https://www.npmjs.com/package/auspice",
   "engines": {
-    "node": "^16 || ^18",
+    "node": "^16 || ^18 || ^20",
     "npm": "^7 || ^8 || ^9"
   },
   "bin": {