[FEATURE] "Problem running prettier with" should output failure

[koppor]

What would you like to change about the program?

I get

Problem running prettier with --write **/*.java

This is output at https://github.com/creyD/prettier_action/blame/8c18391fdc98ed0d884c6345f03975edac71b8f0/entrypoint.sh#L70

I would really like to know which problems there were.

Why do you think this is a cool idea?

Locally, prettier works, but on GitHub, it does not. I wonder, why.
Having some output would help to debug.