Bump Akka.Persistence.Hosting from 1.5.18 to 1.5.20 (#260)

Bumps [Akka.Persistence.Hosting](https://github.com/akkadotnet/Akka.Hosting) from 1.5.18 to 1.5.20.
- [Release notes](https://github.com/akkadotnet/Akka.Hosting/releases)
- [Changelog](https://github.com/akkadotnet/Akka.Hosting/blob/dev/RELEASE_NOTES.md)
- [Commits](akkadotnet/Akka.Hosting@1.5.18...1.5.20)

---
updated-dependencies:
- dependency-name: Akka.Persistence.Hosting
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

src/Directory.Packages.props

@@ -2,7 +2,7 @@
   <PropertyGroup>
     <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
     <AkkaVersion>1.5.15</AkkaVersion>
-    <AkkaHostingVersion>1.5.18</AkkaHostingVersion>
+    <AkkaHostingVersion>1.5.20</AkkaHostingVersion>
 
     <!-- Install from version 5.0.11 included all the way up to 8.x.x, but don't go up a major version -->
     <PostgresLowVersion>5.0.11</PostgresLowVersion>