SK BBAN check

[Simplify]

Discussed in #234

^{Originally posted by jaroborovsky November 3, 2022}
Hi,
can you improve Country specification for SK - Slovakia?
Slovakia has same BBAN validation algorithm as Czech republic.
nbs.sk document in Slovak
SK: { ... bban_validation_func: checkCzechBBAN, ..}
Thanks.

[Simplify]

@jaroborovsky This is implemented and part of release 4.2.0.