Update .nuspec to list git repo information

DEVSIX-3614

Author: ar3em

pdfSweep.nuspec

@@ -16,6 +16,7 @@
     <copyright>Copyright (c) 1998-2020 iText Group NV</copyright>
     <language>en-US</language>
     <tags>itext itext7 itextsharp c# .net csharp pdf cleanup pdfsweep</tags>
+	<repository type="git" url="https://github.com/itext/i7j-pdfsweep.git"/>
     <dependencies>
       <dependency id="itext7" version="7.1.10-SNAPSHOT" />
       <dependency id="Common.Logging" version="3.4.1" />