Update NuGet.targets

change nuget.exe to NuGet.exe for linux building

Author: angelcolmenares

src/.nuget/NuGet.targets

@@ -20,7 +20,7 @@
 
     <PropertyGroup>
         <!-- NuGet command -->
-        <NuGetExePath>$(NuGetToolsPath)\nuget.exe</NuGetExePath>
+        <NuGetExePath>$(NuGetToolsPath)\NuGet.exe</NuGetExePath>
         <NuGetCommand Condition=" '$(OS)' == 'Windows_NT'">"$(NuGetExePath)"</NuGetCommand>
         <NuGetCommand Condition=" '$(OS)' != 'Windows_NT' ">mono --runtime=v4.0.30319 $(NuGetExePath)</NuGetCommand>
 
@@ -74,4 +74,4 @@
               LogStandardErrorAsError="true"
               Condition=" '$(OS)' == 'Windows_NT' " />
     </Target>
-</Project>
+</Project>