Bump Google.Protobuf from 3.21.8 to 3.21.9

Bumps [Google.Protobuf](https://github.com/protocolbuffers/protobuf) from 3.21.8 to 3.21.9.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/generate_changelog.py)
- [Commits](protocolbuffers/protobuf@v3.21.8...v3.21.9)

---
updated-dependencies:
- dependency-name: Google.Protobuf
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Sharpcaster.Test/packages.config

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Google.Protobuf" version="3.21.8" targetFramework="net452" />
+  <package id="Google.Protobuf" version="3.21.9" targetFramework="net452" />
   <package id="Microsoft.Bcl" version="1.1.10" targetFramework="net452" />
   <package id="Microsoft.Bcl.Async" version="1.0.168" targetFramework="net452" />
   <package id="Microsoft.Bcl.Build" version="1.0.21" targetFramework="net452" />

Sharpcaster/Sharpcaster.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.21.8" />
+    <PackageReference Include="Google.Protobuf" Version="3.21.9" />
     <PackageReference Include="Microsoft.CSharp" Version="4.7.0" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="6.0.1" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />

Sharpcaster/packages.config

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Google.Protobuf" version="3.21.8" targetFramework="portable46-net451+win81+wpa81" />
+  <package id="Google.Protobuf" version="3.21.9" targetFramework="portable46-net451+win81+wpa81" />
   <package id="Newtonsoft.Json" targetFramework="portable46-net451+win81+wpa81" version="9.0.1" />
   <package id="Rssdp" version="4.0.4" targetFramework="portable46-net451+win81+wpa81" />
   <package id="Sharpcaster.SocketsForPCL" version="2.0.4" targetFramework="portable46-net451+win81+wpa81" />