Upgrade to Netty 4.2.6

[NilsRenaud]

Version

5.0.4, 4.5.21

Context

Netty introduced a regression on their handling of BouncyCastle library, making it unusable: netty/netty#15627

Current vertx versions (5.0.4 and 4.5.21) use Netty 4.2.5 which contains this regression.

It has been fixed and released in 4.2.6 and 4.1.127.

Steps to reproduce

No response

Do you have a reproducer?

No response