Prepare for future backwards incompatibility of %pyproject_buildrequires

Currently, we see:

    WARNING: Skipping invalid requirement: 8eacfa312d.zip
        Parse error at "'://githu'": Expected stringEnd

It will become an error after https://src.fedoraproject.org/rpms/pyproject-rpm-macros/pull-request/189

With this change, it becomes:

    WARNING: Simplifying 'appdirs@8eacfa312d.zip' to 'appdirs'.

python-platformdirs.spec

@@ -5,7 +5,7 @@ a "user data dir".}
 
 Name:           python-%{srcname}
 Version:        2.0.0
-Release:        2%{?dist}
+Release:        3%{?dist}
 Summary:        Python module for determining appropriate platform-specific dirs
 License:        MIT
 URL:            https://github.com/platformdirs/platformdirs
@@ -28,6 +28,11 @@ BuildRequires:  python3-devel
 %prep
 %autosetup -n %{srcname}-%{version}
 
+# from https://github.com/platformdirs/platformdirs/pull/16
+# can be removed with 2.0.3+
+# let the buildrequires generator know what package is this:
+sed -Ei 's|\b(https://github\.com/ActiveState/appdirs/archive)|appdirs@\1|' tox.ini
+
 
 %generate_buildrequires
 %pyproject_buildrequires -t
@@ -52,6 +57,9 @@ BuildRequires:  python3-devel
 
 
 %changelog
+* Fri Jul 23 2021 Miro Hrončok <mhroncok@redhat.com> - 2.0.0-3
+- Let %%pyproject_buildrequires know we need appdirs
+
 * Fri Jul 23 2021 Fedora Release Engineering <releng@fedoraproject.org> - 2.0.0-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_35_Mass_Rebuild