Update README.md to include other ways to install

[B0pol]

Checklist

• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• I have read the contribution guidelines given at https://github.com/TeamNewPipe/NewPipe/blob/HEAD/.github/CONTRIBUTING.md.
• This issue contains only one feature request. I will open one issue for every feature I want to request.

Describe the feature you want

Update the README. It only lists F-Droid which is often late on releases (and today is late by months on releases due to a bug).

Is your feature request related to a problem? Please describe it

There are other ways to get NewPipe (our F-Droid repository, GitHub release page) and they should be listed, and explain how to choose one.

Additional context

See TeamNewPipe/website#163

How will you/everyone benefit from this feature?

Users checking our README will know what are ways to install NewPipe.

[triallax]

I'll open a PR for this soon.

[B0pol]

In fact there it's already said in updates section, but i was thinking about F-Droid badge and we could also edit this section