Support sklearn >= 0.24

[atusy]

Issue Description

With sklearn >= 0.24, from spmimage.decomposition import KSVD yields ModuleNotFoundError at

https://github.com/hacarus/spm-image/blob/e5b1c960dba6383ce5a5c02bfe028f45b2aa6a63/spmimage/decomposition/ksvd.py#L5

• [x] Check if other sub-modules support sklearn >= 0.24
  • See https://travis-ci.org/github/hacarus/spm-image/jobs/751397735
• [x] Decide whether or not to support sklearn < 0.24
  • release a hotfix to support 0.19 to 0.24 (#93)
  • a release after hotfix will support >= 0.24
• [ ] Update spm-image based on the decision above