Update Python releases

Author: fabaff

setup.py

@@ -27,6 +27,7 @@
         "async_timeout<4",
     ],
     packages=["luftdaten"],
+    python_requires='>=3.8',
     zip_safe=True,
     classifiers=[
         "Development Status :: 3 - Alpha",
@@ -36,8 +37,9 @@
         "Operating System :: MacOS :: MacOS X",
         "Operating System :: Microsoft :: Windows",
         "Operating System :: POSIX",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
         "Topic :: Utilities",
     ],
 )