Update influxdb requirement from = 0.3.13 to = 0.8.0
Update influxdb requirement from = 0.3.13 to = 0.8.0

Updates the requirements on [influxdb](https://github.com/influxdb/influxdb-ruby) to permit the latest version.
- [Release notes](https://github.com/influxdb/influxdb-ruby/releases)
- [Changelog](https://github.com/influxdata/influxdb-ruby/blob/master/CHANGELOG.md)
- [Commits](https://github.com/influxdb/influxdb-ruby/compare/v0.3.13...v0.8.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
sensu-plugins/sensu-plugins-influxdb