Bump either from 1.6.0 to 1.6.1
Bump either from 1.6.0 to 1.6.1

Bumps [either](https://github.com/bluss/either) from 1.6.0 to 1.6.1.
- [Release notes](https://github.com/bluss/either/releases)
- [Commits](https://github.com/bluss/either/compare/1.6.0...1.6.1)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
shssoichiro/oxipng,shssoichiro/oxipng,shssoichiro/oxipng