chore: drop node.js v14 support

Which comes end of life 30 April 2023.

Incidentally, it should fix current github action failure:
```
Run pnpm install
ERROR: This version of pnpm requires at least Node.js v16.14
The current version of Node.js is v14.21.3
Visit https://r.pnpm.io/comp to see the list of past pnpm versions with respective Node.js version support.
Error: Process completed with exit code 1.
```

.github/workflows/validate.yml

@@ -17,7 +17,7 @@ jobs:
 
     strategy:
       matrix:
-        node: ['18', '16', '14']
+        node: ['18', '16']
         # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
 
     steps: