Remove need to sign CLA

[RCheesley]

We no longer need developers to sign the CLA to contribute, so let's remove it from the onboarding docs! 🥳

[RCheesley]

Yep I realised I missed it out and made a commit here: 403a67d

[RCheesley]

Thanks folks!

[RCheesley]

@all-contributors add @IonutOjicaDE for review

[allcontributors[bot]]

@RCheesley

I've put up a pull request to add @IonutOjicaDE! :tada:

[RCheesley]

@all-contributors add @daniellord32 for review

[allcontributors[bot]]

@RCheesley

I've put up a pull request to add @daniellord32! :tada: