Update setup.py

Author: mariusvniekerk

setup.py

@@ -30,7 +30,7 @@
     license="BSD",
     keywords="file",
     packages=["fsspec", "fsspec.implementations"],
-    python_requires=">=3.6",
+    python_requires=">=3.7",
     install_requires=open("requirements.txt").read().strip().split("\n"),
     extras_require={
         ":python_version < '3.8'": ['importlib_metadata'],