release 0.6

Addition of two masker classes: LabelsMasker and MapsMasker, and accompanying tutorial notebooks.
These classes can be used to generate dypac-style maskers for any type of hard or soft parcellation.

What's Changed

• Update nilearn version to 0.9.0 by @htwangtw in #85
• Iss83 masker by @pbellec in #86

New Contributors

• @htwangtw made their first contribution in #85

Full Changelog: v0.5.3...v0.6