Update beautifulsoup4 requirement from ~=4.8.1 to >=4.8.1,<4.10.0 (#720)

Updates the requirements on [beautifulsoup4](http://www.crummy.com/software/BeautifulSoup/bs4/) to permit the latest version.

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

setup.py

@@ -59,7 +59,7 @@ setup(
             "pytest>=5.2.2,<5.5.0",
             "pytest-asyncio~=0.10.0",
             "aiohttp~=3.6.2",
-            "beautifulsoup4~=4.8.1",
+            "beautifulsoup4>=4.8.1,<4.10.0",
             "asgiref~=3.2.3",
             "black~=19.10b0",
         ],