Updating Octo.exe binary to 4.29.0, and updating release notes to let ppl know about how to add newlines in markdown

Author: MarkSiedle

source/VSTSExtensions/OctopusBuildAndReleaseTasks/Tasks/Common/Octo.exe

@@ -104,7 +104,7 @@
             "label": "Custom Notes",
             "defaultValue": "",
             "required": false,
-            "helpMarkDown": "Custom notes appended to Octopus Release notes.",
+            "helpMarkDown": "Custom notes appended to Octopus Release notes. This field supports markdown. To include newlines, you can use HTML linebreaks.",
             "groupName": "releasenotes"
         },
         {