Feature Request: allow a NIXPACKS_BUN_VERSION env var to specify version of Bun in the node provider

[thomasmol]

Feature request

I would like to be able to set an env variable similar to NIXPACKS_NODE_VERSION (https://nixpacks.com/docs/providers/node) but for Bun, so I can set the version of Bun to use.

Motivation

I currently cannot set the version and have to rely on PRs to be merged to use the latest version, e.g.: #1267 #1152 #1113 #1106 #1011 #962 and there are more examples of people wanting to either set or know what version of Bun is being used, e.g.: https://help.railway.com/questions/bun-version-4eec53b8 & https://help.railway.com/questions/bun-version-4eec53b8

An alternative would be to create a standalone Bun provider

Contribution

No response