`devenv up -d` overwrites pid file if processes are already running

[chibidev]

Describe the bug
When running devenv up -d consecutively without stopping previously started processes, devenv overwrites the pid file stored in .devenv/processes.pid, which in turn will break devenv processes down.

To reproduce

1. Create default configuration with devenv init
2. Configure a process to start, e.g. with services.mysql.enable = true;
3. Run devenv up -d
4. Run devenv up -d
5. Run devenv processes down

Expected result:
devenv stops the started processes.

Actual result:

Stopping process with PID 64353
Error:   × Process with PID 64353 not found.

And the processes are still running, because the PID file was overwritten by the second invocation of devenv up -d.

Example files

Version
devenv 1.9.0 (aarch64-darwin)

[domenkozar]

Fix in #2200

[chibidev]

@domenkozar thank you so much!