Document release steps

[fedgiac]

Add documentation on the release steps to make sure everyone can do it. It follows my experience from #111, before I forget all the steps. Can be used as a base later for automating the release proicess.

How to test

Realistically, @kaze-cow should go from memory and spot if I'm missing something.
We'll see how the short guide really fares when we release v0.3.

[kaze-cow]

we should probably test this runsheet out with our next release later this week prior to merge.

[fedgiac]

we should probably test this runsheet out with our next release later this week prior to merge.

My weak preference would be to merge this now so that it's easier to find before the next bump and we can update it if needed. But I don't mind much, we can also wait.

[kaze-cow]

mostly good

we should probably test this runsheet out with our next release later this week prior to merge.
My weak preference would be to merge this now so that it's easier to find before the next bump and we can update it if needed. But I don't mind much, we can also wait.

Since this PR is only updating the readme and the chances of a issue with merge conflicts is low, delaying merge by a couple days to directly validate these instructions seemed like a good idea.

Feel free to take the final decision on this.

[kaze-cow]

only one thing