Bumps [boto3](https://github.com/boto/boto3) from 1.7.4 to 1.7.6.
- [Release notes](https://github.com/boto/boto3/releases)
- [Changelog](https://github.com/boto/boto3/blob/develop/CHANGELOG.rst)
- [Commits](https://github.com/boto/boto3/compare/1.7.4...1.7.6)

Signed-off-by: dependabot[bot] <support@dependabot.com>