(build) Change casing of NuGet Id

- To match new Tool package

Author: gep13

nuspec/nuget/GitReleaseManager.nuspec

@@ -1,7 +1,7 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <package xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
   <metadata xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
-    <id>gitreleasemanager</id>
+    <id>GitReleaseManager</id>
     <title>GitReleaseManager</title>
     <version>$version$</version>
     <authors>GitTools Contributors</authors>