Bump serde_with from 1.9.2 to 1.9.4 (#129)

Bumps [serde_with](https://github.com/jonasbb/serde_with) from 1.9.2 to 1.9.4.
- [Release notes](https://github.com/jonasbb/serde_with/releases)
- [Changelog](https://github.com/jonasbb/serde_with/blob/master/CHANGELOG.md)
- [Commits](jonasbb/serde_with@v1.9.2...v1.9.4)

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

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

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

Author: dependabot[bot]

Cargo.lock

@@ -15,7 +15,7 @@ lazy_static = "1.4.0"
 libc = "0.2.97"
 newtype_derive = "0.1.6"
 serde_json = "1.0"
-serde_with = "1.9.1"
+serde_with = "1.9.4"
 structopt = "0.3"
 thiserror = "1.0"
 toml = "0.5.6"