chore: add Python 3.9 to supported versions (#52)

Author: fubuloubu

.github/workflows/test.yaml

@@ -48,7 +48,7 @@ jobs:
 
         strategy:
             matrix:
-                python-version: [3.6, 3.7, 3.8]
+                python-version: [3.6, 3.7, 3.8, 3.9]
 
         steps:
         - uses: actions/checkout@v2

setup.py

@@ -81,7 +81,7 @@
             "ape_networks=ape_networks._cli:cli",
         ],
     },
-    python_requires=">=3.6,<3.9",
+    python_requires=">=3.6,<3.10",
     extras_require=extras_require,
     py_modules=[
         "ape",
@@ -122,5 +122,6 @@
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
     ],
 )