Bump arrow from 0.15.7 to 0.15.8
Bump arrow from 0.15.7 to 0.15.8

Bumps [arrow](https://github.com/arrow-py/arrow) from 0.15.7 to 0.15.8.
- [Release notes](https://github.com/arrow-py/arrow/releases)
- [Changelog](https://github.com/arrow-py/arrow/blob/master/CHANGELOG.rst)
- [Commits](https://github.com/arrow-py/arrow/compare/0.15.7...0.15.8)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
kk6/python-annict