Add plugins.md traduction

[furlanf]

Qual o objetivo dessa pull request?

• Adição de uma nova tradução
• Correção em uma tradução existente

Qual arquivo foi traduzido/corrigido?

plugins.md

[iaurg]

Boa tradução, obrigado por contribuir.

[jessescn]

Apenas uma besteira que eu queria que tu corrigisse :)

[jessescn]

ótima tradução @furlanf! Obrigado por contribuir conosco e fique a vontade para pegar novas traduções caso queira quando este PR for mergeado! 🎉

[gatsbot]

Holy buckets, @furlanf — we just merged your PR to Gatsby! 💪💜

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