Update bigdecimal requirement from 0.2.0 to 0.3.0 (#37)

Updates the requirements on [bigdecimal](https://github.com/akubera/bigdecimal-rs) to permit the latest version.
- [Release notes](https://github.com/akubera/bigdecimal-rs/releases)
- [Commits](akubera/bigdecimal-rs@v0.2.0...v0.3.0)

---
updated-dependencies:
- dependency-name: bigdecimal
  dependency-type: direct:production
...

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

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

Author: dependabot[bot]

Cargo.toml

@@ -17,7 +17,7 @@ actix = "0.12"
 log = "0.4.11"
 env_logger = "0.9.0"
 serde = "1.0.116"
-bigdecimal = "0.2.0"
+bigdecimal = "0.3.0"
 diesel_migrations = "1.4.0"
 serde_derive = "1.0.116"
 serde_json = "1.0.59"