Make AppVeyor create NuGet packages upon a merge
Make AppVeyor create NuGet packages upon a merge

Prior to generating the packages, the AssemblyInfo.cs is patched with
the build version. Additionally, the assembly informational version
will bear a `-pre` suffix would this build result from a push on a
branch which isn't `master`.

Produced packages will be published as build artifacts.

No packaging will be performed when the build has been triggered from a Pull Request.

psawey/libgit2sharp,jeffhostetler/public_libgit2sharp,oliver-feng/libgit2sharp,dlsteuer/libgit2sharp,shana/libgit2sharp,rcorre/libgit2sharp,github/libgit2sharp,AArnott/libgit2sharp,vorou/libgit2sharp,OidaTiftla/libgit2sharp,libgit2/libgit2sharp,red-gate/libgit2sharp,GeertvanHorrik/libgit2sharp,ethomson/libgit2sharp,oliver-feng/libgit2sharp,whoisj/libgit2sharp,rcorre/libgit2sharp,psawey/libgit2sharp,xoofx/libgit2sharp,jeffhostetler/public_libgit2sharp,shana/libgit2sharp,mono/libgit2sharp,xoofx/libgit2sharp,Skybladev2/libgit2sharp,whoisj/libgit2sharp,Skybladev2/libgit2sharp,ethomson/libgit2sharp,sushihangover/libgit2sharp,vorou/libgit2sharp,OidaTiftla/libgit2sharp,dlsteuer/libgit2sharp,Zoxive/libgit2sharp,AArnott/libgit2sharp,jorgeamado/libgit2sharp,mono/libgit2sharp,AMSadek/libgit2sharp,Zoxive/libgit2sharp,sushihangover/libgit2sharp,AMSadek/libgit2sharp,github/libgit2sharp,PKRoma/libgit2sharp,red-gate/libgit2sharp,jorgeamado/libgit2sharp,GeertvanHorrik/libgit2sharp