Bumps [scratch-blocks](https://github.com/LLK/scratch-blocks) from 0.1.0-prerelease.20200908141031 to 0.1.0-prerelease.20200915140346.
- [Release notes](https://github.com/LLK/scratch-blocks/releases)
- [Commits](https://github.com/LLK/scratch-blocks/commits

)

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