framework: auto-detect causes Out of sync warning #2096

Description

As the title says, framework: auto-detect in paket.dependencies causes the out-of-sync warning to be printed.

Repro steps

1. Create a paket.dependencies with framework: auto-detect, like this:

   source https://nuget.org/api/v2
   framework: auto-detect
   
   nuget Expecto
   

2. Create an F# project with a paket.references:

   Expecto
   

3. $ paket install

4. $ paket restore

Expected behavior

I don't know what would be the best here. Maybe the warning should also tell why the warning is printed, so I can decide whether it is important or not.

Actual behavior

Paket prints the out-of-sync-warning. IMHO because paket.lock says FRAMEWORK: NET45.

Known workarounds

• Change framework: auto-detect to framework: net45 in paket.dependencies
• Use the --ignore-checks flag