Replace PyPI page with README.md (#833)

Co-authored-by: Markus Unterwaditzer <markus-honeypot@unterwaditzer.net>

README.md

@@ -28,8 +28,8 @@ raise ValueError()  # Will also create an event.
 
 # Contributing to the SDK
 
-Please refer to [CONTRIBUTING.md](./CONTRIBUTING.md).
+Please refer to [CONTRIBUTING.md](https://github.com/getsentry/sentry-python/blob/master/CONTRIBUTING.md).
 
 # License
 
-Licensed under the BSD license, see [`LICENSE`](./LICENSE)
+Licensed under the BSD license, see [`LICENSE`](https://github.com/getsentry/sentry-python/blob/master/LICENSE)

setup.py

@@ -8,8 +8,17 @@
 <https://github.com/getsentry/sentry-python>`_ to find out more.
 """
 
+import os
 from setuptools import setup, find_packages
 
+here = os.path.abspath(os.path.dirname(__file__))
+
+
+def get_file_text(file_name):
+    with open(os.path.join(here, file_name)) as in_file:
+        return in_file.read()
+
+
 setup(
     name="sentry-sdk",
     version="0.19.1",
@@ -21,7 +30,8 @@
         "Changelog": "https://github.com/getsentry/sentry-python/blob/master/CHANGES.md",
     },
     description="Python client for Sentry (https://sentry.io)",
-    long_description=__doc__,
+    long_description=get_file_text("README.md"),
+    long_description_content_type='text/markdown',
     packages=find_packages(exclude=("tests", "tests.*")),
     # PEP 561
     package_data={"sentry_sdk": ["py.typed"]},