Bump chardet from 3.0.4 to 4.0.0 (#5333)

Bumps [chardet](https://github.com/chardet/chardet) from 3.0.4 to 4.0.0.
- [Release notes](https://github.com/chardet/chardet/releases)
- [Commits](chardet/chardet@3.0.4...4.0.0)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
(cherry picked from commit b0ed732)

requirements/base.txt

@@ -6,7 +6,7 @@ async-timeout==3.0.1
 attrs==20.3.0
 brotlipy==0.7.0
 cchardet==2.1.7
-chardet==3.0.4
+chardet==4.0.0
 gunicorn==20.0.4
 idna-ssl==1.1.0; python_version<"3.7"
 typing_extensions==3.7.4.3