Stop using deprecated zero-argument pypi_source macro

https://docs.fedoraproject.org/en-US/packaging-guidelines/Python/#pypi_source

python-typing-extensions.spec

@@ -1,13 +1,11 @@
-%global srcname typing_extensions
-
 Name:      python-typing-extensions
 Version:   4.2.0
-Release:   2%{?dist}
+Release:   3%{?dist}
 Summary:   Python Typing Extensions
 
 License:   Python
 URL:       https://pypi.org/project/typing-extensions/
-Source0:   %{pypi_source}
+Source0:   %{pypi_source typing_extensions}
 
 BuildArch: noarch
 
@@ -51,7 +49,7 @@ Summary:       %{summary}
 
 
 %prep
-%autosetup -n %{srcname}-%{version}
+%autosetup -n typing_extensions-%{version}
 
 %generate_buildrequires
 %pyproject_buildrequires
@@ -76,6 +74,9 @@ Summary:       %{summary}
 %doc README.rst
 
 %changelog
+* Mon May 23 2022 Benjamin A. Beasley <code@musicinmybrain.net> - 4.2.0-3
+- Stop using deprecated zero-argument pypi_source macro
+
 * Sun May 22 2022 Jonny Heggheim <hegjon@gmail.com> - 4.2.0-2
 - Removed unused build depenencies