build(deps): bump ecdsa from 0.16.7 to 0.16.8

Bumps [ecdsa](https://github.com/RustCrypto/signatures) from 0.16.7 to 0.16.8.
- [Commits](RustCrypto/signatures@ecdsa/v0.16.7...ecdsa/v0.16.8)

---
updated-dependencies:
- dependency-name: ecdsa
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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