Update NuGet spec version to v1.3.0-beta1

Author: augustoproiete

NuGet/ExcelDna.IntelliSense/ExcelDna.IntelliSense.nuspec

@@ -2,7 +2,7 @@
 <package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
     <metadata>
         <id>ExcelDna.IntelliSense</id>
-        <version>1.2.0</version>
+        <version>1.3.0-beta1</version>
         <title>Excel-DNA IntelliSense Extension</title>
         <authors>Excel-DNA Contributors</authors>
         <owners>Excel-DNA Contributors</owners>