Bump tools/swift-sdk-generator from 80b0a28 to a9f8e2a

Bumps [tools/swift-sdk-generator](https://github.com/apple/swift-sdk-generator) from `80b0a28` to `a9f8e2a`.
- [Commits](swiftlang/swift-sdk-generator@80b0a28...a9f8e2a)

---
updated-dependencies:
- dependency-name: tools/swift-sdk-generator
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]