Add dateutil dependecy for PlainTasks (#5895)

repository/dependencies.json

@@ -133,6 +133,20 @@
 				}
 			]
 		},
+		{
+			"name": "dateutil",
+			"load_order": "50",
+			"description": "The dateutil module provides powerful extensions to the datetime module available in the Python standard library",
+			"author": "vovkkk",
+			"issues": "https://github.com/vovkkk/sublime-dateutil/issues",
+			"releases": [
+				{
+					"base": "https://github.com/vovkkk/sublime-dateutil",
+					"tags": true,
+					"sublime_text": "*"
+				}
+			]
+		},
 		{
 			"name": "dicttoxml",
 			"load_order": "50",