Merge pull request chainer#8618 from chainer/bump-version

Bump version and add cupy packages

Merge pull request chainer#8613 from chainer/bump-docker-7.8

Bump Dockerfiles to v.7.8.0

bump version

Merge pull request chainer#8577 from kmaehashi/bump-version

Bump version to v7.7.0

Merge pull request chainer#8559 from emcastillo/bump

Bump version to v7.4.0

Merge pull request chainer#8547 from kmaehashi/bump-v7.2.0

Bump version to v7.2.0

Merge pull request chainer#8538 from emcastillo/version_71

Bump version to v7.1.0

Merge pull request chainer#8539 from asi1024/v6.7.0

Bump version to v6.7.0

Merge pull request chainer#8504 from emcastillo/70

Bump version to v7.0.0

Merge pull request chainer#8506 from niboshi/v6.6.0

Bump version to v6.6.0