build(deps): bump bstr from 0.2.14 to 0.2.15
Bumps [bstr](https://github.com/BurntSushi/bstr) from 0.2.14 to 0.2.15.
- [Release notes](https://github.com/BurntSushi/bstr/releases)
- [Commits](https://github.com/BurntSushi/bstr/compare/0.2.14...0.2.15)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>