build(deps): update minicbor requirement from 0.14 to 0.15 (#72)

Updates the requirements on [minicbor](https://gitlab.com/twittner/minicbor) to permit the latest version.
- [Release notes](https://gitlab.com/twittner/minicbor/tags)
- [Changelog](https://gitlab.com/twittner/minicbor/blob/master/CHANGELOG.md)
- [Commits](https://gitlab.com/twittner/minicbor/compare/minicbor-v0.14.0...minicbor-v0.15.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

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

pallas-codec/Cargo.toml

@@ -13,5 +13,5 @@ authors = [
 ]
 
 [dependencies]
-minicbor = { version = "0.14", features = ["std", "half", "derive"] }
+minicbor = { version = "0.15", features = ["std", "half", "derive"] }
 

pallas-crypto/Cargo.toml

@@ -13,7 +13,7 @@ authors = [
 ]
 
 [dependencies]
-minicbor = { version = "0.14" }
+minicbor = { version = "0.15" }
 hex = "0.4"
 cryptoxide = { version = "0.4.1" }
 thiserror = "1.0"