update UML notebook

Author: rambasnet

notebooks/UML.ipynb

@@ -81,7 +81,7 @@
     "    - search for `PlantUML` in Extensions and click on `Settings` menu\n",
     "    - click `Workspace` tab set PlantUML: Render to `Remote`\n",
     "    - click `Workspace` tab set PlantUML: Output Format to `png`\n",
-    "    - enter server URL: `http://www.plantuml.com/plantuml/png/` in PlantUML: Server\n",
+    "    - enter server URL: `http://www.plantuml.com/plantuml` in PlantUML: Server\n",
     "- to render UML diagrams:\n",
     "- on VS Code, create .plantuml file and enter `option+D` (Mac) or `alt+D` (Win)\n",
     "- to save image file:\n",