Rename module to github.com/microsoft/go-winio

The Microsoft GitHub organization uses a lowercase 'm', which other go modules from Microsoft also use. This module using an uppercase M can cause problems in certain build systems when using macOS which uses a case-insensitive build system by default: NixOS/nixpkgs#273998

go.mod

@@ -1,4 +1,4 @@
-module github.com/Microsoft/go-winio
+module github.com/microsoft/go-winio
 
 go 1.17