docs: fix grammar - it's -> its

[jaller94]

Title

Fix grammar: it's -> its

Description

A few places use "it's" (= it is), when they should use the possessive "its" (the dog and its ball).

Notes & open questions

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works

[SgtPooki]

Thanks so much for the contribution! FYI the documentation in these readme.md files are generated from the package documentation jsdoc in the index.ts files for each of the packages in the monorepo

[achingbrain]

The part of the README in question is generated by aegir so I think we're all good here - ref: ipfs/aegir#1566