Build a new image just to get rid of CVEs

[JPLachance]

Greetings,

When we scan the alxrem/prometheus-logstash-exporter container image with a tool like Snyk, Snyk reports a ton of vulnerabilities in this container base image:

Tested 14 dependencies for known issues, found 23 issues.

Base Image     Vulnerabilities  Severity
alpine:3.12.3  23               2 critical, 16 high, 3 medium, 2 low

Recommendations for base image upgrade:

Minor upgrades
Base Image   Vulnerabilities  Severity
alpine:3.13  0                0 critical, 0 high, 0 medium, 0 low

Here, upgrading the base image would remove a lot of noise.

On top of that, Alpine 3.12 is reaching end of live on 01 May 2022.

Since the Dockerfile is always using the latest version of alpine, all we need is to build a new image, ship it to Docker Hub as a version 0.8.0, and all our security tools will stop telling us we are doing bad things.

Can we do it? I would do it myself, but I don't have access to this project CI/CD setup, nor to the Docker Hub project.

Thanks!

[LHozzan]

Hi @JPLachance .
I attempted to fix some CVEs in this PR.
@alxrem What do you think about it?