Update index.md

1 job for master in 18 seconds (queued for 3 seconds)
Name Stage Failure
failed
pages Test
  File "/usr/local/lib/python3.8/site-packages/plantuml_markdown.py", line 281, in _render_remote_uml_image
return PlantUML("%s/%s/" % (self.config['server'], img_format)).processes(plantuml_code)
File "/usr/local/lib/python3.8/site-packages/plantuml.py", line 173, in processes
raise PlantUMLHTTPError(response, content)
File "/usr/local/lib/python3.8/site-packages/plantuml.py", line 56, in __init__
if not self.message:
AttributeError: 'PlantUMLHTTPError' object has no attribute 'message'
Cleaning up file based variables
ERROR: Job failed: exit code 1