Bump greenstalk from 1.0.1 to 2.0.2

Bumps [greenstalk](https://github.com/justinmayhew/greenstalk) from 1.0.1 to 2.0.2.
- [Commits](justinmayhew/greenstalk@v1.0.1...v2.0.2)

---
updated-dependencies:
- dependency-name: greenstalk
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -3,7 +3,7 @@ arrow==0.15.5
 envparse==0.2.0
 falcon==2.0.0
 freezing-model @ https://github.com/freezingsaddles/freezing-model/archive/0.7.20.tar.gz
-greenstalk==1.0.1
+greenstalk==2.0.2
 gunicorn==22.0.0
 python-mimeparse==1.6.0
 six==1.16.0