Melhorias no CONTRIBUTING.md

[trevineju]

No contributing.md de querido-diario havia:

Sometimes the community organizes events for solving multiple issues in a short amount of time. Especially in these cases, an issue or pull request may be considered abandoned when is waiting for the contributor but doesn't receive updates for a couple of weeks. Just let us know you need more time, so we don't end up closing it by mistake.

Este conteúdo deve existir no contributing.md deste repositório

[trevineju]

agora, há um repositório de -backend; precisa adicionar à lista do ecossistema

[jufajardini]

Posso trabalhar nesta aqui, se não estiver resolvida :)

[robokbr]

Traduzindo para inglês	Translating to english

I can work on this one if it's not resolved :)

[jufajardini]

agora, há um repositório de -backend; precisa adicionar à lista do ecossistema

Acho que isso aqui já tá resolvido.

[robokbr]

Traduzindo para inglês	Translating to english

now, there is a -backend repository; need to add to ecosystem list

I think this is already resolved.