* Data staleness warnings are now only shown if the `getCompatibleVersions()` or `getAllVersions()` functions are called - previously they were shown whenever the module was loaded, which meant many `browserslist` consumers were seeing the warning despite not targeting Baseline, especially those who were consuming `browserslist` in a pre-compiled format via `next.js`.
* Adds new conditions for these warnings to be displayed which should only warn users for whom data freshness is critical:
  * The feature cut off data must be within the last two months, i.e. `widelyAvailableOnDate: today + >2 years and 4 months` or `newly available` in a `browserslist` query.
  * The module data must be more than 2 months old.
  * None of the suppression mechanisms below are in use.
* Introduces suppression options for these warning via the `options` objects and environment variables:
  * Adds a new `suppressWarnings` boolean to the `getCompatibleVersions()` and `getAllVersions()` 
  * Respects the existing [`BROWSERSLIST_IGNORE_OLD_DATA`](browserslist/browserslist@0ae7155) environment variable.
  * Respects a new `BASELINE_BROWSER_MAPPING_IGNORE_OLD_DATA` environment variable.
* Adds explanatory text to the docs for how to avoid such warnings when reproducible builds are a requirement.
* Change warning text to be package manager agnostic and mention the possibility of pre-compiled data.

Fixes: #105 #107 #109