Bump AkkaVersion from 1.5.11 to 1.5.12 (#336)

Bumps `AkkaVersion` from 1.5.11 to 1.5.12.

Updates `Akka.Persistence.Query` from 1.5.11 to 1.5.12
- [Release notes](https://github.com/akkadotnet/akka.net/releases)
- [Changelog](https://github.com/akkadotnet/akka.net/blob/dev/RELEASE_NOTES.md)
- [Commits](akkadotnet/akka.net@1.5.11...1.5.12)

Updates `Akka.Streams` from 1.5.11 to 1.5.12
- [Release notes](https://github.com/akkadotnet/akka.net/releases)
- [Changelog](https://github.com/akkadotnet/akka.net/blob/dev/RELEASE_NOTES.md)
- [Commits](akkadotnet/akka.net@1.5.11...1.5.12)

Updates `Akka.Persistence.TCK` from 1.5.11 to 1.5.12
- [Release notes](https://github.com/akkadotnet/akka.net/releases)
- [Changelog](https://github.com/akkadotnet/akka.net/blob/dev/RELEASE_NOTES.md)
- [Commits](akkadotnet/akka.net@1.5.11...1.5.12)

---
updated-dependencies:
- dependency-name: Akka.Persistence.Query
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: Akka.Streams
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: Akka.Persistence.TCK
  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.Build.props

@@ -20,7 +20,7 @@
     <NetFrameworkTestVersion>net471</NetFrameworkTestVersion>
     <NetStandardLibVersion>netstandard2.0</NetStandardLibVersion>
 
-    <AkkaVersion>1.5.11</AkkaVersion>
+    <AkkaVersion>1.5.12</AkkaVersion>
     <AkkaHostingVersion>1.5.12</AkkaHostingVersion>
     <XunitVersion>2.5.0</XunitVersion>
     <TestSdkVersion>17.6.3</TestSdkVersion>