Update snapshottest requirement from ~=0.5.1 to >=0.5.1,<0.7.0 (#582)
Update snapshottest requirement from ~=0.5.1 to >=0.5.1,<0.7.0 (#582)

Updates the requirements on [snapshottest](https://github.com/syrusakbary/snapshottest) to permit the latest version.
- [Release notes](https://github.com/syrusakbary/snapshottest/releases)
- [Changelog](https://github.com/syrusakbary/snapshottest/blob/master/CHANGELOG.md)
- [Commits](https://github.com/syrusakbary/snapshottest/compare/0.5.1...0.6.0)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
larq/larq