This commit refactors where custom environment variables are set in the
workspace and decouples agent specific configs from the `agentssh.Server`.
To reproduce all functionality, `agentssh.Config` is introduced.
The custom environment variables are now configured in `agent/agent.go`
and the agent retains control of the final state. This will allow for
easier extension in the future and keep other modules decoupled.
* chore: add /v2 to import module path
go mod requires semantic versioning with versions greater than 1.x
This was a mechanical update by running:
```
go install github.com/marwan-at-work/mod/cmd/mod@latest
mod upgrade
```
Migrate generated files to import /v2
* Fix gen
