setup.cfg: Replace tabs

We use 4 spaces more commonly.

Change-Id: I4479cc907645f4c1c972ebba4b36d972a338ccb5
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

setup.cfg

@@ -4,30 +4,30 @@ author = OpenStack
 author_email = openstack-discuss@lists.openstack.org
 summary = Refresh system configuration
 description_file =
-	README.rst
+    README.rst
 home_page = http://opendev.org/openstack/os-refresh-config
 python_requires = >=3.8
 classifier =
-	Development Status :: 4 - Beta
-	Environment :: Console
-	Environment :: OpenStack
-	Intended Audience :: Developers
-	Intended Audience :: Information Technology
-	License :: OSI Approved :: Apache Software License
-	Operating System :: OS Independent
-	Programming Language :: Python
-	Programming Language :: Python :: Implementation :: CPython
-	Programming Language :: Python :: 3
-	Programming Language :: Python :: 3 :: Only
-	Programming Language :: Python :: 3.8
-	Programming Language :: Python :: 3.9
-	Programming Language :: Python :: 3.10
-	Programming Language :: Python :: 3.11
-	Programming Language :: Python :: 3.12
+    Development Status :: 4 - Beta
+    Environment :: Console
+    Environment :: OpenStack
+    Intended Audience :: Developers
+    Intended Audience :: Information Technology
+    License :: OSI Approved :: Apache Software License
+    Operating System :: OS Independent
+    Programming Language :: Python
+    Programming Language :: Python :: Implementation :: CPython
+    Programming Language :: Python :: 3
+    Programming Language :: Python :: 3 :: Only
+    Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3.9
+    Programming Language :: Python :: 3.10
+    Programming Language :: Python :: 3.11
+    Programming Language :: Python :: 3.12
 
 [files]
 packages =
-	os_refresh_config
+    os_refresh_config
 scripts =
     tools/dib-run-parts