build(deps): bump error-chain from 0.12.3 to 0.12.4 (#189)

Bumps [error-chain](https://github.com/rust-lang-nursery/error-chain) from 0.12.3 to 0.12.4.
- [Release notes](https://github.com/rust-lang-nursery/error-chain/releases)
- [Changelog](https://github.com/rust-lang-nursery/error-chain/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rust-lang-nursery/error-chain/compare/0.12.3...0.12.4)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Cargo.lock

@@ -444,9 +444,9 @@ dependencies = [
 
 [[package]]
 name = "error-chain"
-version = "0.12.3"
+version = "0.12.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "be51ed50e75656c17216bdd4326914466db0c91b9b246b12962a00284d06566b"
+checksum = "2d2f06b9cac1506ece98fe3231e3cc9c4410ec3d5b1f24ae1c8946f0742cdefc"
 dependencies = [
  "backtrace",
  "version_check 0.9.2",