use node.js 20

GitHub has deprecated node.js 16 and requires node Actions to migrate to
version 20 by "spring 2024". [1] Update to node.js 20 to avoid
deprecation warnings.

This fixes #684

[1]
https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

action.yml

@@ -33,5 +33,5 @@ inputs:
     description: 'Filter results by the reason for the build; Defaults to "all"'
     default: 'all'
 runs:
-  using: 'node16'
+  using: 'node20'
   main: 'dist/index.js'

package-lock.json

@@ -34,7 +34,7 @@
   },
   "devDependencies": {
     "@types/jest": "^28.1.8",
-    "@types/node": "^16.11.7 <18.0.0",
+    "@types/node": "^20.9.0 <22.0.0",
     "@types/unzipper": "^0.10.9",
     "@typescript-eslint/parser": "^5.62.0",
     "@vercel/ncc": "^0.38.1",