Bump babel from 2.9.0 to 2.9.1 in /deploy

Bumps [babel](https://github.com/python-babel/babel) from 2.9.0 to 2.9.1.
- [Release notes](https://github.com/python-babel/babel/releases)
- [Changelog](https://github.com/python-babel/babel/blob/master/CHANGES)
- [Commits](https://github.com/python-babel/babel/compare/v2.9.0...v2.9.1)

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

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

deploy/requirements.txt

@@ -2,7 +2,7 @@ alabaster==0.7.12
 alembic==1.4.3
 aniso8601==8.0.0
 attrs==20.3.0
-babel==2.9.0
+babel==2.9.1
 bcrypt==3.2.0
 beautifulsoup4==4.9.3
 blinker==1.4