Deprecation warnings on PHP 8.4

[ADmad]

src/JWT.php:199
Firebase\JWT\JWT::encode(): Implicitly marking parameter $keyId as nullable is deprecated, the explicit nullable type must be used instead

src/JWK.php:55
Firebase\JWT\JWK::parseKeySet(): Implicitly marking parameter $defaultAlg as nullable is deprecated, the explicit nullable type must be used instead

src/JWK.php:96
Firebase\JWT\JWK::parseKey(): Implicitly marking parameter $defaultAlg as nullable is deprecated, the explicit nullable type must be used instead

[lolli42]

Confirmed. Would be great to get this merged and released - PHP 8.4 is alpha2 now and frameworks start implementing compatibility, libraries should have compatible releases.

[lolli42]

Ping.

Note current CI is (unnoticed) red, which is fixed by PR #572 as well as drive-by.

Note there is PR #573 as dupe already.