docs: 📝 add image description

Signed-off-by: Mario Vejlupek <mario@vejlupek.cz>

Author: devopsmariocom

Dockerfile

@@ -1,6 +1,7 @@
 FROM python:3.11.4-slim-bookworm
 
 LABEL org.opencontainers.image.source https://github.com/Container-Driven-Development/Python-AWS-Exporter-Base
+LABEL org.opencontainers.image.description "Base image for Python scripts exporting AWS resources using boto library to Prometheus"
 
 ENTRYPOINT ["/usr/local/bin/python"]