build(deps-dev): bump @storybook/addon-storyshots from 6.5.9 to 6.5.15

Bumps [@storybook/addon-storyshots](https://github.com/storybookjs/storybook/tree/HEAD/addons/storyshots/storyshots-core) from 6.5.9 to 6.5.15.
- [Release notes](https://github.com/storybookjs/storybook/releases)
- [Changelog](https://github.com/storybookjs/storybook/blob/v6.5.15/CHANGELOG.md)
- [Commits](https://github.com/storybookjs/storybook/commits/v6.5.15/addons/storyshots/storyshots-core)

---
updated-dependencies:
- dependency-name: "@storybook/addon-storyshots"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]