Code Quality: Update source to show .NET Foundation copyright (#1813)

* Change package company to .NET Foundation in `Directory.Build.props`

* Update package manufacturer in WIX project

* Update copyright in `sys` module

Author: Lamparter

Directory.Build.props

@@ -21,8 +21,8 @@
     <AssemblyFileRevision Condition="'$(ReleaseLevel)' == 'final'">1000</AssemblyFileRevision>
 
     <Product>IronPython</Product>
-    <Company>IronPython Team</Company>
-    <Copyright>© IronPython Contributors</Copyright>
+    <Company>.NET Foundation</Company>
+    <Copyright>© .NET Foundation and Contributors</Copyright>
     <AssemblyVersion>$(MajorVersion).$(MinorVersion).$(MicroVersion).$(AssemblyRevision)</AssemblyVersion>
     <FileVersion>$(MajorVersion).$(MinorVersion).$(MicroVersion).$(AssemblyFileRevision)</FileVersion>
     <InformationalVersion>$(MSBuildProjectName) $(MajorVersion).$(MinorVersion).$(MicroVersion) $(ReleaseLevel) $(ReleaseSerial)</InformationalVersion>

Package/msi/Version.wxi

@@ -1,4 +1,4 @@
 <Include Id="VersionNumberInclude" xmlns="http://wixtoolset.org/schemas/v4/wxs">
   <?define ProductShortName = "IronPython" ?>
-  <?define Manufacturer = "IronPython Team" ?>
+  <?define Manufacturer = ".NET Foundation" ?>
 </Include>

Src/IronPython/Modules/sys.cs

@@ -29,7 +29,7 @@ public static class SysModule {
         // argv is set by PythonContext and only on the initial load
         public static readonly string byteorder = BitConverter.IsLittleEndian ? "little" : "big";
         // builtin_module_names is set by PythonContext and updated on reload
-        public const string copyright = "Copyright (c) IronPython Team";
+        public const string copyright = "Copyright (c) .NET Foundation and Contributors";
 
         private static string GetPrefix() {
             string prefix;