set XF Verions File to be hidden (#8128)

.gitignore

@@ -69,4 +69,4 @@ caketools/
 *.binlog
 .ionide/**
 /.nuspec
-XamarinFormsVersionFile.txt
+.XamarinFormsVersionFile.txt

Version.targets

@@ -56,7 +56,7 @@
 
     <Message Condition="$(CI) and '$(BUILD_REASON)' == 'Schedule'" Importance="high" Text="##vso[build.addbuildtag]$(NightlyTag)"/>
     <ItemGroup>
-       <XamarinFormsVersionFile Include="../XamarinFormsVersionFile.txt"/>
+       <XamarinFormsVersionFile Include="../.XamarinFormsVersionFile.txt"/>
        <XamarinFormsVersionLine Include="$(PackageVersion)"/>
     </ItemGroup>
     

build.cake

@@ -174,7 +174,7 @@ Task("_NuGetPack")
     .Does(() =>
     {
         var nugetVersionFile = 
-            GetFiles("XamarinFormsVersionFile.txt");
+            GetFiles(".XamarinFormsVersionFile.txt");
         var nugetversion = FileReadText(nugetVersionFile.First());
 
         Information("Nuget Version: {0}", nugetversion);