Remove setup.py in favor of pyproject.toml

setuptools doesn't work without `setup.cfg`/`setup.py`.

flint had some minor issues - pypa/flit#525 / pypa/flit#488

poetry does not support namespace packages

pyproject.toml

@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools", "wheel"]
+build-backend = "setuptools.build_meta"

setup.cfg

@@ -1,28 +1,33 @@
 [metadata]
-name = astronomer-operators
+name = astronomer-providers
 version = 1.1.0
-url = https://github.com/astronomer/astronomer-operators/
+url = https://github.com/astronomer/astronomer-providers/
 author = Astronomer
 author_email = [email protected]
 description = Airflow Providers containing Deferrable Operators & Sensors from Astronomer
 long_description = file: README.rst
 license = Apache License 2.0
 license_files = LICENSE.txt
 classifiers =
+    Development Status :: 4 - Beta
     Environment :: Web Environment
+    Intended Audience :: Developers
     License :: OSI Approved :: Apache Software License
     Operating System :: OS Independent
     Programming Language :: Python
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
+project_urls =
+    Source Code=https://github.com/astronomer/astronomer-providers/
+    Homepage=https://astronomer.io/
 
 [options]
 python_requires = >=3.7
 packages = find_namespace:
 include_package_data = true
-namespace_packages = astronomer,astronomer.operators
+namespace_packages = astronomer,astronomer.providers
 install_requires =
     aiohttp
     aiofiles