Add PyPI metadata

pyproject.toml

 [tool.poetry]
 name = "calendarweek"
-version = "0.1.0"
+version = "0.1.0.post0"
 description = "Utilities for working with calendar weeks in Python and Django"
 authors = ["Dominik George <nik@naturalnet.de>", "Jonathan Weth <git@jonathanweth.de>"]
 license = "MIT"
+homepage = "https://edugit.org/nik/django-calendarweek"
+repository = "https://edugit.org/nik/django-calendarweek"
+documentation = "https://edugit.org/nik/django-calendarweek"
+classifiers = [
+    "Development Status :: 4 - Beta",
+    "Framework :: Django",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "Topic :: Software Development :: Libraries :: Python Modules",
+    "Topic :: Software Development :: Localization",
+    "Typing :: Typed"
+]
 
 [tool.poetry.dependencies]
 python = "^3.7"