expiring-todo-comments: Add date option

[mmkal]

This could be useful a few ways:

1. Testing lint configs
2. Finding todos that expire soon but not yet
3. Testing the rule itself
4. Finding very out of date todos, e.g. by setting the date one year in the past

@fisker @sindresorhus I'll add tests and docs once we've established the feature is something that would be considered Docs and tests added. I was going to make an issue but it was about the same amount of effort to make the (runtime) code change as PR. I did it in the GitHub UI 🙃

👇 something like what I'll add to the docs

date

Type: string (date format)
Default: <today>

For TODOs with date deadlines, this option makes them trigger only if the deadline is later than the specified date. You could set this to a date in the future to find TODOs that expire soon, or set it far in the past if you want to ignore recently-expired TODOs.

The format must match json-schema's date.

examples

Find tech debt that has grown up and gone to college by triggering the rule for TODOs with old dates:

"unicorn/expiring-todo-comments": [
	"error",
	{
		"date": "2000-01-01"
	}
]

Prepare for the future by triggering the rule for TODOs with dates from the next millennium:

"unicorn/expiring-todo-comments": [
	"error",
	{
		"date": "3000-01-01"
	}
]

[sindresorhus]

Makes sense to me.

---

I use something similar when I make macOS apps where I can pass a flag to see APIs that will be deprecated in the future.

[sindresorhus]

Tests are failing

[mmkal]

Not sure why it's failing on CI but not locally. Will debug.

[fisker]

eslint-plugin-unicorn/rules/expiring-todo-comments.js

Line 334 in 3286381

const shouldIgnore = options.ignoreDatesOnPullRequests && ci.isPR;

caused by this line?

[mmkal]

@fisker that was it - thanks!