build(deps): bump external/spdlog from 1e6250e to 276ee5f

Bumps [external/spdlog](https://github.com/gabime/spdlog) from `1e6250e` to `276ee5f`.
- [Release notes](https://github.com/gabime/spdlog/releases)
- [Commits](gabime/spdlog@1e6250e...276ee5f)

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

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