Bump bottle from 0.11.2 to 0.12.19 in /examples/gui/bottle

Bumps [bottle](https://github.com/bottlepy/bottle) from 0.11.2 to 0.12.19.
- [Release notes](https://github.com/bottlepy/bottle/releases)
- [Changelog](https://github.com/bottlepy/bottle/blob/master/docs/changelog.rst)
- [Commits](bottlepy/bottle@0.11.2...0.12.19)

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

Author: dependabot[bot]

examples/gui/bottle/requirements.txt

@@ -1,4 +1,4 @@
 # -------------------------------------------------------------------
 # if you want to use this frontend uncomment these
 # -------------------------------------------------------------------
-bottle==0.11.2
+bottle==0.12.19