I used `force:source:retrieve` to retrieve the given list of components (classes, workflows etc) and committed the files to git. Now I want to deploy these components to higher environments like QA and Prod from Git. 

`force:source:deploy` - I can't use this since it doesn't have the options like validate only or run local tests etc.. So I am planning to use `force:source:convert` to convert into mdapi format but even this does not have an option to convert a list of metadata, it converts all the source code in the root folder.

What are the options to convert given list of metadata (package.xml/list of files) to mdapi format and then deploy to sandbox/prod from git.