[path_provider] Allow win32 up to version 4.x (flutter#3820)

Adds compatibility with version 4.x of `win32`. No breaking changes impacted the plugin, so this just relaxes the constraint.

Fixes flutter#125355

Author: stuartmorgan-g

packages/path_provider/path_provider_windows/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.1.6
+
+* Adds compatibility with `win32` 4.x.
+
 ## 2.1.5
 
 * Clarifies explanation of endorsement in README.

packages/path_provider/path_provider_windows/pubspec.yaml

@@ -2,7 +2,7 @@ name: path_provider_windows
 description: Windows implementation of the path_provider plugin
 repository: https://github.com/flutter/packages/tree/main/packages/path_provider/path_provider_windows
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+path_provider%22
-version: 2.1.5
+version: 2.1.6
 
 environment:
   sdk: ">=2.17.0 <4.0.0"
@@ -21,7 +21,7 @@ dependencies:
     sdk: flutter
   path: ^1.8.0
   path_provider_platform_interface: ^2.0.0
-  win32: ">=2.1.0 <4.0.0"
+  win32: ">=2.1.0 <5.0.0"
 
 dev_dependencies:
   flutter_test: