Test on Python 3.9 and add trove classifier

Author: tcbegley

.github/workflows/tests.yml

@@ -53,9 +53,9 @@ jobs:
     needs: build
     runs-on: 'ubuntu-latest'
     strategy:
-      max-parallel: 4
+      max-parallel: 6
       matrix:
-        python-version: [2.7, 3.5, 3.6, 3.7, 3.8]
+        python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9]
     services:
       hub:
         image: selenium/hub:3.141.59-gold

noxfile.py

@@ -17,7 +17,7 @@ def lint(session):
     session.run("isort", "--check", *SOURCES)
 
 
-@nox.session(python=["2.7", "3.5", "3.6", "3.7", "3.8"])
+@nox.session(python=["2.7", "3.5", "3.6", "3.7", "3.8", "3.9"])
 def test(session):
     session.install("pytest")
     session.install("dash[testing]")

pyproject.toml

@@ -15,7 +15,8 @@ classifiers = [
     "Programming Language :: Python :: 3.5",
     "Programming Language :: Python :: 3.6",
     "Programming Language :: Python :: 3.7",
-    "Programming Language :: Python :: 3.8"
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9"
 ]
 requires = ["dash>=1.9.0"]
 description-file = "landing-page.md"