Tarball update when working with cloned repositories

[jhein32]

When downloading sources using git_configand changing options such as tagor keep_git_dir, the source tarball doesn't get recreated to reflect these changes. EB keeps working with the "old" tarball. No warning is given and the issues is not even in the documentation.

A possible way forward, is for EasyBuild to include its own meta-data, e.g. the git_config options into the tarball. When there is a mismatch of the options in the config and the tarball, one could give one or more of:

• Warning
• Interactive option to download a new source, this would require some mechanism to handle non-interactive EB use

This was discussed with @boegel in the EB slack.