arduino-cli lib install has exit status 0 when library is not found

[per1234]

Bug Report

Current behavior

$ arduino-cli lib install foo
Error resolving dependencies for foo: looking for library: library foo not found

$ echo $?
0

Expected behavior

I would expect the command to have exit status 1 when the library is not found.

This would make the command's behavior consistent with arduino-cli core install:

$ ./arduino-cli core install foo:bar
Error during install: finding platform dependencies: package foo not found

$ echo $?
1

It would also be consistent with the behavior of the Arduino IDE's CLI:

$ ./arduino --install-library foo 2>/dev/null
Downloading libraries index... 
Downloading libraries index... 
Updating list of installed libraries
Selected library is not available
$ echo $?
1

Environment

• CLI version (output of arduino-cli version): Version: 0.10.0-rc1 Commit: ebc28e1
• OS and platform: Ubuntu 64 bit, Windows 64 bit

Additional context

Exit status 1 on failed library installation would be helpful for the use of Arduino CLI in automation applications. With the current behavior, the failure of the library installation is only manifested by compilation failure due to the missing header file. That makes troubleshooting the issue more difficult than if the process had failed at the library installation stage of the process.