build(deps): Bump System.Text.Json

Bumps System.Text.Json from 5.0.2 to 8.0.4.

---
updated-dependencies:
- dependency-name: System.Text.Json
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

src/CloudNative.CloudEvents.SystemTextJson/CloudNative.CloudEvents.SystemTextJson.csproj

@@ -9,7 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="System.Text.Json" Version="5.0.2" Condition="'$(TargetFramework)'=='netstandard2.0' or '$(TargetFramework)'=='netstandard2.1'" />
+    <PackageReference Include="System.Text.Json" Version="8.0.4" Condition="'$(TargetFramework)'=='netstandard2.0' or '$(TargetFramework)'=='netstandard2.1'" />
   </ItemGroup>
 
   <ItemGroup>