package.json repository url not read

[LuisPeregrinaIBM2]

When creating VSIX and using a relative image in the README.md it says:
ERROR Couldn't detect the repository where this extension is published. The image 'preview.png' will be broken in README.md. Please provide the repository URL in package.json or use the --baseContentUrl and --baseImagesUrl options.

However, there is a repo url in package.json:

{
	...
	"repository": {
		"type": "git",
		"url": "https://***.git"
	},

[joaomoreno]

Is it a github repo? Is it a public repo?

[LuisPeregrinaIBM2]

github enterprise, public repo

[LuisPeregrinaIBM2]

either way, parameter baseImagesUrl works, so either the message is missing some additional info (github.com repos only) or it's not parsed correctly.