feat: Label renaming and import statements

[joeyparrish]

This adds two main features: label renaming and import statements.

Label renaming is an extension of the work done by @larsks in PR #60. To the renaming support in #60 (alias field), I added a list-of-strings field called aliases, to better support single configs that can be used across repositories. For example, each repo could have a different existing bug label that you may to rename to unify them:

- name: "Type: bug"
  aliases:
    - bug
    - defect
  description: Something isn't working
  color: d73a4a

The import statement further enhances our ability to share configs across repos. Common fields needed by all repos (such as Type: bug) could be placed in a common config file. Then, each repo has its own config file with its unique labels, and the common ones get imported. For example:

# common.yaml
- name: "Type: bug"
  aliases:
    - bug
    - defect
  description: Something isn't working
  color: d73a4a

# repo1.yaml
- import: common.yaml

- name: "Platform: iOS"
  description: Issues specific to iOS
  color: d73a4a

Finally, this makes some additional changes I found useful in testing and development:

• Error early instead of trying to change a label with a question mark in the name.
• Error early if description is too long. GitHub will reject these labels, so we should identify them early and provide a clear message.
• Serialize label changes. Doing them in parallel does not make the process much faster, but it does make the logs more difficult to read.
• Fix silent errors from main.
• Add dry-run flag. Useful for testing a large migration before making it final.

Closes #59

[joeyparrish]

@larsks, @micnncim, please let me know if you have any feedback. Thanks!

[joeyparrish]

@micnncim, I can continue using my fork indefinitely if I must, but I always prefer to contribute upstream. Please let me know if you have feedback. Thanks!

[micnncim]

Sorry for being too late. Some feedback I can give you as of now:

• Please separate the PR per feature/fix
• Please create an issue for the import feature and discuss it there

This would make your change easier to be merged into this project.

[joeyparrish]

Issue #59 already existed for the renaming feature. I've updated it with the details of my extension to allow multiple aliases.

I've filed #69 for the import feature.

[maxisam]

This is a really nice feature. Any chance to merge this?