outdated ignore-constraints should find updates

[Uli-Armbruster]

source https://nuget.org/api/v2

nuget Castle.Windsor !~> 3.3

NUGET
  remote: https://nuget.org/api/v2
  specs:
    Castle.Core (3.3.0)
    Castle.Windsor (3.3.0)
      Castle.Core (>= 3.3.0)

$ .paket/paket outdated --ignore-constraints
Paket version 0.18.2.0
found: D:\Development\Repository\paket.dependencies
Resolving packages:
  - fetching versions for Castle.Windsor
    - exploring Castle.Windsor 3.3.0
  - fetching versions for Castle.Core
    - exploring Castle.Core 3.3.0
Outdated packages found:
  * (none)
12 seconds - ready.

Paket should also find Castle.Core 3.3.3

[agross]

I think the problem is the ! in the Castle.Windsor constraint.

[forki]

I'm pretty sure we have to relax the ResolverStrategy in https://github.com/fsprojects/Paket/blob/master/src/Paket.Core/FindOutdated.fs#L24

Should be an easy fix.
I'm a bit in a hurry so I mark it up-for-grabs and will check in a couple of days if someone fixed it ;-)