Stop testing on end-of-life versions of Node.js

`node-version: [latest, lts/*, lts/-1, lts/-2]`
 Currently:
* latest: v25.9.0
* lts/*: v24.14.1
* lts/-1: v22.22.2
* lts/-2: v20.20.2

* https://nodejs.org/en/about/previous-releases
* https://github.com/actions/setup-node?tab=readme-ov-file#supported-version-syntax

Author: cclauss

.github/workflows/test.yml

@@ -82,7 +82,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node-version: ['12', '14', '16', '18', '20', 'lts/*']
+        node-version: [latest, lts/*, lts/-1, lts/-2]
     steps:
       - uses: actions/checkout@v6
         with: