Bump bottle from 0.12.13 to 0.12.20

Bumps [bottle](https://github.com/bottlepy/bottle) from 0.12.13 to 0.12.20.
- [Release notes](https://github.com/bottlepy/bottle/releases)
- [Changelog](https://github.com/bottlepy/bottle/blob/master/docs/changelog.rst)
- [Commits](bottlepy/bottle@0.12.13...0.12.20)

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,3 +1,3 @@
-bottle==0.12.13
+bottle==0.12.20
 requests>=2.20.0
 gunicorn==19.9.0