Wrong conjugation for "ficar"

[daelmaak]

First of all, thanks for the great lib!

Describe the bug

"Indicativo pretérito perfeito simples" gives "fir)" for "nós". ["Indicativo", "Indicativo pretérito perfeito simples", "nós", "fir)"]

To Reproduce
Steps to reproduce the behavior:

    conjugator = Conjugator(language = 'pt')
    conjugatedVerb = conjugator.conjugate('ficar')
    conjugatedVerb.iterate()

Expected behavior
Correct form is returned - "ficámos"