build(deps): Bump python from 3.7-slim to 3.8.1-slim in /backend

Bumps python from 3.7-slim to 3.8.1-slim.

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

Author: dependabot-preview[bot]

backend/Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.7-slim
+FROM python:3.8.1-slim
 
 ADD tools /src/tools
 ADD backend /src/backend