Use readme file as package long description (#615)

setup.py

@@ -1,9 +1,19 @@
+"""esphome-dashboard setup script."""
+
+import os
 from setuptools import setup, find_packages
 
+here = os.path.abspath(os.path.dirname(__file__))
+
+with open(os.path.join(here, "README.md"), encoding="utf-8") as readme:
+    long_description = readme.read()
+
 setup(
     name="esphome-dashboard",
     version="20240429.0",
     description="ESPHome dashboard",
+    long_description=long_description,
+    long_description_content_type="text/markdown",
     url="https://github.com/esphome/dashboard",
     author="Nabu Casa",
     author_email="[email protected]",