Fix pkgconfig name collision on Windows

This fix is related to conan-io#10341
The previous fix did not take into account cases insensitive
filesystems. As a result the issue was still present on Windows.
OpenEXR is an example of affected recipe.

conan/tools/gnu/pkgconfigdeps.py

@@ -336,7 +336,7 @@ def _update_pc_files(info):
         # if it does not already exist in components one
         # Issue related: https://github.com/conan-io/conan/issues/10341
         pkg_name = _get_package_name(self._dep, self._build_context_suffix)
-        if f"{pkg_name}.pc" not in pc_files:
+        if not f"{pkg_name}.pc".lower() in [x.lower() for x in pc_files]:
             package_info = _PCInfo(pkg_name, pkg_requires, f"Conan package: {pkg_name}",
                                    self._dep.cpp_info, _get_package_aliases(self._dep))
             # It'll be enough creating a shortened PC file. This file will be like an alias