Fix: 3.3.0 relase due failures when publishing gem

[kares]

The rake task rake vendor did not halt on a ./gradlew vendor failure.
The failure itself was caused by the gradle copy task not specifying a filtering charset,
which lead to sha1sum failures due messing up non-ascii characters e.g.:

393c393
<     family_replacement: 'Seznam prohlížeč'
---
>     family_replacement: 'Seznam prohl????e??'
395c395
<   # Coc Coc browser, based on Chrome (used in Vietnam)
---
>   #??Coc Coc browser, based on Chrome (used in Vietnam)
4305c4305
<   # @ref: www.tecno-mobile.com/‎
---
>   # @ref: www.tecno-mobile.com/???

closing #72
related: elastic/logstash#12869

[andsel]

LGTM