feat: Support for manually providing version number

First off, awesome tool! Excited to see it grow. Some projects that I have deployed are relatively new, and don't have a nice API that allows Argus to be able to query the deployed version number. While an API to automatically determine it is ideal circumstance, I don't mind babysitting the config file in Argus. So I'd love to just be able have something like this work... ``` deployed_version: method: MANUAL version: '1.2.3' ``` In the meantime, it's a bit of a workaround, but this works by using beeceptor's echoing: ``` deployed_version: method: GET url: 'https://echo.free.beeceptor.com?ver=1.2.3' json: parsedQueryParams.ver ``` Thanks again!