Bump Microsoft.Owin in /samples/MailChimpReceiver.Selfhost (#153)

Bumps [Microsoft.Owin](https://github.com/aspnet/AspNetKatana) from 3.0.1 to 4.2.2.
- [Release notes](https://github.com/aspnet/AspNetKatana/releases)
- [Commits](aspnet/AspNetKatana@v3.0.1...v4.2.2)

---
updated-dependencies:
- dependency-name: Microsoft.Owin
  dependency-type: direct:production
...

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

Author: dependabot[bot]

samples/MailChimpReceiver.Selfhost/packages.config

@@ -4,7 +4,7 @@
   <package id="Microsoft.AspNet.WebApi.Core" version="5.2.2" targetFramework="net452" />
   <package id="Microsoft.AspNet.WebApi.Owin" version="5.2.2" targetFramework="net452" />
   <package id="Microsoft.AspNet.WebApi.OwinSelfHost" version="5.2.2" targetFramework="net452" />
-  <package id="Microsoft.Owin" version="3.0.1" targetFramework="net452" />
+  <package id="Microsoft.Owin" version="4.2.2" targetFramework="net452" />
   <package id="Microsoft.Owin.Host.HttpListener" version="2.0.2" targetFramework="net452" />
   <package id="Microsoft.Owin.Hosting" version="2.0.2" targetFramework="net452" />
   <package id="Newtonsoft.Json" version="13.0.1" targetFramework="net452" />