Fix deprecations related to setuptools

setup.cfg

@@ -1,7 +1,7 @@
 [metadata]
 name = tinytag
 author = Tom Wallroth
-author-email = tomwallroth@gmail.com
+author_email = tomwallroth@gmail.com
 url = https://github.com/devsnd/tinytag
 description = Read music meta data and length of MP3, OGG, OPUS, MP4, M4A, FLAC, WMA and Wave files
 keywords =
@@ -25,15 +25,12 @@ classifiers =
     Topic :: Multimedia :: Sound/Audio
     Topic :: Multimedia :: Sound/Audio :: Analysis
 license = MIT
-license-file = LICENSE
-long-description = file: README.md
-long-description-content-type = text/markdown
+license_files = LICENSE
+long_description = file: README.md
+long_description_content_type = text/markdown
 
 [options]
 python_requires = >= 2.7
-setup_requires =
-  setuptools >= 38.6
-  pip >= 10
 include_package_data = True
 packages = find:
 install_requires =