Bump chardet from 3.0.4 to 4.0.0

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

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

requirements.txt

@@ -1,7 +1,7 @@
 astroid==2.0.4
 cachetools==2.1.0
 certifi==2018.10.15
-chardet==3.0.4
+chardet==4.0.0
 elasticsearch==6.3.1
 falcon==1.4.1
 google-api-core==1.5.1