Bump external/SPIRV-Tools from 5ed21eb to e5c1498

Bumps [external/SPIRV-Tools](https://github.com/KhronosGroup/SPIRV-Tools) from `5ed21eb` to `e5c1498`.
- [Release notes](https://github.com/KhronosGroup/SPIRV-Tools/releases)
- [Commits](KhronosGroup/SPIRV-Tools@5ed21eb...e5c1498)

---
updated-dependencies:
- dependency-name: external/SPIRV-Tools
  dependency-type: direct:production
...

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