Add expiration dates

[ericcornelissen]

Allow users to set an expiration date for a rule in the configuration file. This allows users to not forget about rules they don't want to last forever, for example when the upstream project promised to resolve the deprecation and you want to make sure you don't forget about it.

For example our own current config could be adjusted like

{
  "publint@^0.2.12": {
    "npm-packlist@^5.0.0": {
      "*": {
        "#ignore": "tracked in https://github.com/bluwy/publint/issues/11",
        "#expire": "2024-12-31"
      }
    }
  }
}

to force a re-review of the rule by the end of the current year.

[ericcornelissen]

Resolved with 1bdd3fddae2395c3b0ef9c580dae35e618af571f