Bump python from 3.8-alpine to 3.12-alpine

Bumps python from 3.8-alpine to 3.12-alpine.

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

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

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.8-alpine
+FROM python:3.12-alpine
 
 ARG USERNAME=json_exporter