Bump mockall from 0.11.4 to 0.12.0 (#393)

Bumps [mockall](https://github.com/asomers/mockall) from 0.11.4 to 0.12.0.
- [Changelog](https://github.com/asomers/mockall/blob/master/CHANGELOG.md)
- [Commits](asomers/mockall@v0.11.4...v0.12.0)

---
updated-dependencies:
- dependency-name: mockall
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Cargo.toml

@@ -115,7 +115,7 @@ version = "0.3.2"
 version = "2.0.4"
 
 [dev-dependencies.mockall]
-version = "0.11.4"
+version = "0.12.0"
 
 [dev-dependencies.pretty_assertions]
 version = "1.4.0"