v0.23

This is version 0.23 of moulin. Here are the changes:

What's Changed

• git.py: added directory tracking to the Moulin git builder by @Mishytca in #92
• yocto.py: layers not being removed from bblayers.conf by @Mishytca in #94
• Dev/mykhailo androsiuk by @Mishytca in #96
• Revert "yocto.py: update layers in bblayers.conf" by @lorc in #98
• Dev/mykhailo androsiuk by @Mishytca in #97
• builder: custom_script: use src_stamps as dependency by @lorc in #101
• args argument can be given as value list by @dsemenets in #103
• Remove the absolute path usage for tools by @rshym in #102
• Add tests for yaml_wrapper by @Deedone in #107
• Add support for Zephyr snippets by @Deedone in #108
• Support fetch feature in custom_script builder by @dsemenets in #104
• Add submodules support for git, fix small issue with repo and bump version by @lorc in #110

Full Changelog: v0.21...v0.23