Bump to 0.4.0 (#2366)

Merge pull request #1457 from fox0430/develop

v0.3.0

Merge pull request #1403 from fox0430/develop

v0.2.8.0

Merge pull request #1373 from fox0430/develop

v0.2.7

Merge pull request #1331 from fox0430/hotfix

Fix moe.nimble: Fix moe version

Merge pull request #1329 from fox0430/develop

v0.2.6

Merge pull request #1295 from fox0430/hotfix

v0.2.5.1

Merge pull request #1290 from fox0430/update-moe.nimble

Fix moe.nimble

Merge pull request #1231 from fox0430/hotfix

v0.2.4.1

Merge pull request #1223 from fox0430/develop

v0.2.4