How to get TFS to ask user for a version number during manual build request?

How to get TFS to ask user for a version number during manual build request?

I want to make the builds on a specific branch advance the version number
in AssemblyInfo.cs files and in Package.nuspec files according to the
Semantic Versioning convension.
In order to do this, when code is merged into this specific branch, I want
to:
Ask the merging user for a new version number, preferably during merge
(then run build during check-in) or when the user runs a manual build,
preferably displaying a custom dialog which displays current version
number and asks if API has been broken, expanded or if changes do not
affect API, then save the new version number aside.
Apply version number to AssemblyInfo.cs file(s).
Apply version number to Package.nuspec file(s).
Run build.
Publish resulting NuGet packages.
I am not sure how to get the first step working, as it is interactive.
Has anyone tried such as approach before?
Are there any known solutions?
Any tips how to solve this?