0.6.1: Fix compatibility with Ruby < 2.6

Fixed

• Compatibility with Ruby < 2.6 due to usage of new Hash#merge(*others) with multiple arguments in 0.6.0

0.6.0: Redefine default tags at runtime

Added

• Yabeda.with_tags to redefine default tags for limited amount of time–for all metrics measured during a block execution. @Envek

Fixed

• Default tags were not sent to adapters for metrics declared before default_tag declaration. @Envek