Explanation:
Grammar tells us that verbs can also be used as nouns. It sounds a bit awkward using both verbs in parallel with the same complement "it". It's not grammatically wrong but just a matter of style, as we know the pronoun "it" should be replacing the same thing and doesn't have to be mentioned twice. As though, I'd suggest re-writing the sentence using one of the verbs as a noun, for example: Feel free to copy or make a contribution to it. Or Feel free to make a copy or contribute to it. It should sound more elegant and better English.
