Input validation

Luxon is a library for working with dates and times in JavaScript. On the 1.x branch prior to 1.38.1, the 2.x branch prior to 2.5.2, and the 3.x branch on 3.2.1, Luxon’s `DateTime.fromRFC2822() has quadratic (N^2) complexity on some specific inputs. This causes a noticeable slowdown for inputs with lengths above 10k characters. Users providing untrusted data to this method are therefore vulnerable to (Re)DoS attacks. This issue also appears in Moment as CVE-2022-31129. Versions 1.38.1, 2.5.2, and 3.2.1 contain patches for this issue. As a workaround, limit the length of the input.