Bump Newtonsoft.Json from 9.0.1 to 12.0.3

Bumps [Newtonsoft.Json](https://github.com/JamesNK/Newtonsoft.Json) from 9.0.1 to 12.0.3.
- [Release notes](https://github.com/JamesNK/Newtonsoft.Json/releases)
- [Commits](JamesNK/Newtonsoft.Json@9.0.1...12.0.3)

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

src/common.props

@@ -12,7 +12,7 @@
     <XunitVersion>2.4.1</XunitVersion>
     <TestSdkVersion>16.3.0</TestSdkVersion>
     <HyperionVersion>0.9.10</HyperionVersion>
-    <NewtonsoftJsonVersion>9.0.1</NewtonsoftJsonVersion>
+    <NewtonsoftJsonVersion>12.0.3</NewtonsoftJsonVersion>
     <NBenchVersion>1.2.2</NBenchVersion>
     <ProtobufVersion>3.10.0</ProtobufVersion>
     <NetCoreTestVersion>netcoreapp2.1</NetCoreTestVersion>