🚀 New release: Ergo protocol reference client 6.0.0-RC1 (v6.0.0-RC1)

Corresponding to the following commit in Sigma interpreter: https://github.com/ergoplatform/sigmastate-interpreter/pull/1027/commits/fe3b9076a318c9d4dde493d0206592b933f0e3cb

## What's Changed

* New numeric methods (bitwise operations, shifts etc) for the UnsignedBigInt type

* Rule #215 deactivated on 6.0 activation. This rule prevents from starting voting for unknown parameter. With that deactivation, from now it is possible to introduce new parameters in non-breaking way.

* Replaced Sigma validation rules tuning

* New parameter, number of subblocks per block

Check it out here: https://github.com/ergoplatform/ergo/releases/tag/v6.0.0-RC1