php-jwt requires "alg" parameter in JWKS
Software that relies on php-jwt (such as GLPI) needs an "alg" subkey in JWKS.
Problem is that a single RSA key can be used by multiple JWE algs, and "alg" is single valued, in addition to being non-mandatory
A workaround in some competing solutions is to declare "alg": "RS256"
even if it's technically false