Remove outdated System.Text.Json pinned reference (#1436)

Author: paulirwin

.build/dependencies.props

@@ -80,7 +80,6 @@
     <SystemRuntimeInteropServicesRuntimeInformationPackageVersion>4.3.0</SystemRuntimeInteropServicesRuntimeInformationPackageVersion>
     <SystemTextEncodingCodePagesPackageVersion>4.3.0</SystemTextEncodingCodePagesPackageVersion>
     <SystemTextEncodingCodePagesPackageVersion Condition=" '$(TargetFramework)' == 'net472' ">5.0.0</SystemTextEncodingCodePagesPackageVersion>
-    <SystemTextJsonPackageVersion>6.0.10</SystemTextJsonPackageVersion>
     <SystemTextRegularExpressionsPackageVersion>4.3.1</SystemTextRegularExpressionsPackageVersion>
     <TimeZoneConverterPackageVersion>6.1.0</TimeZoneConverterPackageVersion>
   </PropertyGroup>

src/Lucene.Net.Analysis.OpenNLP/Lucene.Net.Analysis.OpenNLP.csproj

@@ -55,10 +55,6 @@
     <PackageReference Include="ICU4N" Version="$(ICU4NPackageVersion)" />
     <PackageReference Include="IKVM" Version="$(IKVMPackageVersion)" />
     <PackageReference Include="IKVM.Maven.Sdk" Version="$(IKVMMavenSdkPackageVersion)" />
-
-    <!-- This is a transitive dependency of IKVM, but the version it references is vulnerable. We are currently blocked from upgrading
-        IKVM due to the Azure DevOps limitation of 10GB for a single build agent, so we have to add this reference instead. -->
-    <PackageReference Include="System.Text.Json" Version="$(SystemTextJsonPackageVersion)" />
   </ItemGroup>
 
   <ItemGroup>