update readme badges

[bjlittle]

🚀 Pull Request

Description

This PR updates and refreshes the README.md badges.

Notably, badges to the GHA CI and RTD have been added, and the badge to the now defunct cirris-ci has been removed.

The changes render as follows:

See here.

[trexfeathers]

You're not gonna like this 😅

I'm quite strongly against using HTML in markdown files unless it's absolutely necessary. It's not consistent with the ​.md​ format, and is harder to read.

I appreciate that this is the only way to get centralised text/badges, but I just don't think it's worth it. That's why I introduced markdown badges in #179 a year ago (which you were happy to merge).

It would also obvs be way easier for me to review this if the format was consistent.

[bjlittle]

I personally don't mind HTML within Markdown, particularly when Markdown simply can't do the job.

So now we have this instead...

😞

[trexfeathers]

I personally don't mind HTML within Markdown, particularly when Markdown simply can't do the job.

So now we have this instead...

😞

Sounds like we both have strong opinions. I'll happily bow to a third opinion from another dev (which would make it a quorum either way).

[bjlittle]

@trexfeathers I honestly don't greatly mind. Tis fine 👍

[trexfeathers]

Badges look good to me, and feel free to try alternatives to the commas.

Codacy has also picked up some boo boos I made in my original reformatting. Could you address those?

[bjlittle]

So we now have this...