Bump Akka.Logger.Serilog from 1.5.7 to 1.5.12.1 (#236)

Bumps [Akka.Logger.Serilog](https://github.com/akkadotnet/Akka.Logger.Serilog) from 1.5.7 to 1.5.12.1.
- [Release notes](https://github.com/akkadotnet/Akka.Logger.Serilog/releases)
- [Changelog](https://github.com/akkadotnet/Akka.Logger.Serilog/blob/dev/RELEASE_NOTES.md)
- [Commits](https://github.com/akkadotnet/Akka.Logger.Serilog/commits)

---
updated-dependencies:
- dependency-name: Akka.Logger.Serilog
  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]

src/Directory.Packages.props

@@ -4,7 +4,7 @@
   </PropertyGroup>
   <!-- Akka.NET Package Versions -->
   <ItemGroup>
-    <PackageVersion Include="Akka.Logger.Serilog" Version="1.5.7" />
+    <PackageVersion Include="Akka.Logger.Serilog" Version="1.5.12.1" />
     <PackageVersion Include="Akka.Bootstrap.Docker" Version="0.5.3" />
   </ItemGroup>
   <!-- Phobos Package Versions -->