Security Advisory: json_decode() expects parameter 1 to be string, array given

**Problem:**
1. Run command ```monitor:health```
2. Warning occurs: ```WARNING Security Advisory: json_decode() expects parameter 1 to be string, array given```

**Solution:**
Remove ```$advisories = @json_decode($advisories);``` in ```ZendDiagnostics\Check\SecurityAdvisory``` and the warning is gone.