[Fix] adapt gitignore for depends after da63933

[Rechi]

Description

Depends get installed in different directories depending if the are build with debugging disabled or not.
This adapts the gitignore for depends to ignore the build files.
@wsnipex is this correct?

Types of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the Code guidelines of this project
• My change requires a change to the documentation, either Doxygen or wiki
• I have updated the documentation accordingly
• I have read the CONTRIBUTING document
• I have added tests to cover my change
• All new and existing tests passed

[wsnipex]

Thanks, looks like I forgot about that ;)