build(deps): Bump tenacity from 6.1.0 to 6.2.0 in /bot

Bumps [tenacity](https://github.com/jd/tenacity) from 6.1.0 to 6.2.0.
- [Release notes](https://github.com/jd/tenacity/releases)
- [Commits](jd/tenacity@6.1.0...6.2.0)

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

Author: dependabot-preview[bot]

bot/requirements.txt

@@ -4,5 +4,5 @@ libmozdata==0.1.68
 pytoml==0.1.21
 pytz==2020.1
 pyyaml==5.3.1
-tenacity==6.1.0
+tenacity==6.2.0
 zstandard==0.13.0