Add more validations to labels name and description

[srealmoreno]

What

The Github api has some validations besides character length.

• Label Name:

  1. Must contain more than native emojis

     When using a name that only contains emojis, this error occurs:

• Description:

  2. 4-byte characters are not allowed

     

Details

my labels.yml

- name: 😀 😃 😄 😁
  color: "536266"
  description: This is a name only contains emojis

- name: bug 🐞
  color: d73a4a
  description: 
    This is a description that contains emojis 4-byte unicode 🐞

With that file, the script will fail with the following message:

GitHub Error:
POST /repos/srealmoreno/test-label-sync/labels
422: Validation Failed

It would be great if you showed the error with --dry-run option.

Similar issues #42 #135