Update README.md

[boopdadm]

add troubleshooting info for connection error with UART

[andrey-pr]

This manual should be different for different popular distributives

[Hadatko]

Thank you for this PR. I was trying to run app with sudo to get rid of adding user under dial group, but app doesn't work. So i added user into group and it works now.

[boopdadm]

This manual should be different for different popular distributives

what do you mean ?

[andrey-pr]

I mean that different distribution of linux have different troubles with serial port and they require different solutions. For example, some old versions of Ubuntu had modem manager that blocked all serial ports and had to stop or remove it. On other distribution or new versions of ubuntu this problem not exists.
So if you provide some solution, please mark what distribution does to related to

[boopdadm]

@Hadatko what distribution did you try on ?

[Hadatko]

@boopdadm kubuntu 24.04

[boopdadm]

@andrey-pr does that look better to you ?