feat(managers): add Paket manager support

[fpellet]

Changes

First implementation to support paket (https://github.com/fsprojects/Paket), a package manager opensource for dotnet.
Not all features are supported. Ready:

• lock file maintenance
• update nuget packages

Context

• closes #11211

Documentation (please check one with an [x])

• [X] I have updated the documentation, or
• [ ] No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• [ ] Code inspection only, or
• [ ] Newly added/modified unit tests, or
• [ ] No unit tests but ran on a real repository, or
• [X] Both unit tests + ran on a real repository

[fpellet]

Can you please also test this on a test_repo and link it here.

Cases to test:

1. single dep gets updated

2. multiple deps get updated

I tested both cases manually (you can see the MRs). Here is the repo: https://github.com/fpellet/renovate-paket There are two dependencies to update (Xunit and Fake).

I just modified it to create two directories, one with a single dependency and one with two dependencies. It's ok for you?

[purkhusid]

What would it take to get this PR back on track?

[RahulGautamSingh]

What would it take to get this PR back on track?

we don't accept managers which are using external tools to extract dependencies. so you need to extract those yourself.

This ☝🏻 and other suggested changes

[fpellet]

https://github.com/renovatebot/renovate/pull/37287#discussion_r2318556021 Fixed