Bump System.Text.Json from 6.0.5 to 8.0.4 in /src/Tinify

Bumps System.Text.Json from 6.0.5 to 8.0.4.

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

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

src/Tinify/Tinify.csproj

@@ -41,7 +41,7 @@
 	</ItemGroup>
 
 	<ItemGroup>
-		<PackageReference Include="System.Text.Json" Version="6.0.5" />
+		<PackageReference Include="System.Text.Json" Version="8.0.4" />
 	</ItemGroup>
 
 </Project>