Update README.rst

[rdemaria]

update madx version and simplify the support message not to discourage people too much (to be discussed)

[coveralls]

Coverage remained the same at 93.438% when pulling cc8ae32 on update-readme into 6ee6cb6 on master.

[coldfix]

It's fine for me but you might want to discuss this with Laurent first. I wrote the disclaimer after asking Laurent and at the time he told me that I can distribute this as long as I write a disclaimer so that people will not ask him about bugs produced by cpymad.

[rdemaria]

I will check, maybe @tpersson can comment as well. Do you know why the python badge in the readme does not show Python 3.8?

[coldfix]

I hope it should be fine now that you're part of the team.

Do you know why the python badge in the readme does not show Python 3.8?

Oh, I guess that's because I forgot to update the classifiers in setup.cfg. We should add 3.8 and 3.9, and should remove 3.3, 3.4 and probably also 2.7 (pip will lose support for 2.7 at the end of the year). Maybe better just replace all the minor versions by Python :: 3

Update: I've changed this for v1.6.1.