Bump Apache.Avro and Newtonsoft.Json in /src/net (#594)

Bumps [Apache.Avro](https://github.com/apache/avro) and [Newtonsoft.Json](https://github.com/JamesNK/Newtonsoft.Json). These dependencies needed to be updated together.

Updates `Apache.Avro` from 1.11.3 to 1.12.0
- [Release notes](https://github.com/apache/avro/releases)
- [Commits](apache/avro@release-1.11.3...release-1.12.0)

Updates `Newtonsoft.Json` from 10.0.3 to 13.0.1
- [Release notes](https://github.com/JamesNK/Newtonsoft.Json/releases)
- [Commits](JamesNK/Newtonsoft.Json@10.0.3...13.0.1)

---
updated-dependencies:
- dependency-name: Apache.Avro
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: Newtonsoft.Json
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

src/net/KNet.Serialization.Avro/KNet.Serialization.Avro.csproj

@@ -18,7 +18,7 @@
  <None Include="..\..\documentation\articles\usageSerDes.md" Pack="true" PackagePath="\" />
  </ItemGroup>
  <ItemGroup>
- <PackageReference Include="Apache.Avro" Version="1.11.3" />
+ <PackageReference Include="Apache.Avro" Version="1.12.0" />
  <PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>