Bump System.Text.Json from 6.0.6 to 7.0.0 (#153)

Bumps [System.Text.Json](https://github.com/dotnet/runtime) from 6.0.6 to 7.0.0.
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](https://github.com/dotnet/runtime/commits)

---
updated-dependencies:
- dependency-name: System.Text.Json
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

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

Author: dependabot[bot]

src/Serilog.Sinks.Grafana.Loki/Serilog.Sinks.Grafana.Loki.csproj

@@ -25,7 +25,7 @@
 
     <ItemGroup>
         <PackageReference Include="Serilog" Version="2.12.0" />
-        <PackageReference Include="System.Text.Json" Version="6.0.6" />
+        <PackageReference Include="System.Text.Json" Version="7.0.0" />
     </ItemGroup>
 
     <ItemGroup>