HTTP Proxy Support

When using [maven-dependency-submission-action](https://github.com/advanced-security/maven-dependency-submission-action) this library does not support `http_proxy` or `https_proxy`. Breaking self-hosted runners in environments requiring proxy for access to the github api.

Most other github actions libraries seem to handle this implictly.

The issue names no file, test, or entry point, so start by tracing the library's GitHub API requests and how the maven-dependency-submission-action invokes them. Done means those requests honor http_proxy and https_proxy so the action works on self-hosted runners that require a proxy.

Vom Indexierungsmodell aus dem Issue-Text verfasst.