[Feature Request] Add support for ARM64 architecture (linux/arm64/v8)

[mgaldamez]

Description
Hello,

I am trying to use smtp2graph in my infrastructure, but my server is running on an ARM64 architecture. When trying to pull the Docker image, it fails because there is no manifest available for this architecture.

Steps to Reproduce
Run the following command on an ARM64 machine:

docker pull evantrow/smtp2graph:latest

Error Message

latest: Pulling from evantrow/smtp2graph
no matching manifest for linux/arm64/v8 in the manifest list entries

[EvanTrow]

The image its not built for arm. Feel free to make a PR for it.

[mgaldamez]

Feature added in PR #5