add badges for download and PyPI version

[niccokunzmann]

It adds two badges.

shows which version is there - quite useful to know and nice to see that it changes after deploy

makes sure we know that this is important and used a lot!

[geier]

While we are at it, should we remove the Travis Badge and also add a github workflow badge?

[coveralls]

Pull Request Test Coverage Report for Build 2814362254

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 90.758%

---

Totals
Change from base Build 2684673460:	0.0%
Covered Lines:	1149
Relevant Lines:	1266

---

💛 - Coveralls

[geier]

Sorry, only saw #364 now.

[niccokunzmann]

No problem, nice to think alike.

[geier]

@niccokunzmann this now conflicts, do you want to resolve or should I?

[niccokunzmann]

I can do it. It just takes a while.