nuget(deps): bump Microsoft.AspNetCore.WebSockets from 2.1.1 to 2.2.1

Bumps [Microsoft.AspNetCore.WebSockets](https://github.com/aspnet/AspNetCore) from 2.1.1 to 2.2.1.
- [Release notes](https://github.com/aspnet/AspNetCore/releases)
- [Commits](dotnet/aspnetcore@2.1.1...v2.2.1)

---
updated-dependencies:
- dependency-name: Microsoft.AspNetCore.WebSockets
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

src/core/Wyam.Hosting/Wyam.Hosting.csproj

@@ -16,7 +16,7 @@
     <PackageReference Include="Microsoft.AspNetCore.Owin" Version="2.1.1" />
     <PackageReference Include="Microsoft.AspNetCore.Server.Kestrel" Version="2.1.3" />
     <PackageReference Include="Microsoft.AspNetCore.StaticFiles" Version="2.1.1" />
-    <PackageReference Include="Microsoft.AspNetCore.WebSockets" Version="2.1.1" />
+    <PackageReference Include="Microsoft.AspNetCore.WebSockets" Version="2.2.1" />
     <PackageReference Include="Microsoft.Extensions.FileProviders.Composite" Version="2.1.1" />
     <PackageReference Include="Microsoft.Extensions.FileProviders.Embedded" Version="2.1.1" />
     <PackageReference Include="Microsoft.Extensions.FileProviders.Physical" Version="2.1.1" />