Bump pyjwt from 1.5.0 to 2.4.0

Bumps [pyjwt](https://github.com/jpadilla/pyjwt) from 1.5.0 to 2.4.0.
- [Release notes](https://github.com/jpadilla/pyjwt/releases)
- [Changelog](https://github.com/jpadilla/pyjwt/blob/master/CHANGELOG.rst)
- [Commits](https://github.com/jpadilla/pyjwt/compare/1.5.0...2.4.0)

---
updated-dependencies:
- dependency-name: pyjwt
  dependency-type: direct:production
...

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

requirements.txt

@@ -2,7 +2,7 @@ certifi==2017.4.17
 chardet==3.0.3
 idna==2.5
 plaid-python==2.0.2
-PyJWT==1.5.0
+PyJWT==2.4.0
 PySocks==1.6.7
 pytz==2017.2
 requests==2.17.3