changed_charts output behaves incorrectly

[bo0tzz]

The documentation for the output says:

Will be an empty string if no updates were detected

But that's not what the script does:

chart-releaser-action/cr.sh

Lines 103 to 107 in 3e001cb

	else
	echo "Nothing to do. No chart changes detected."
	echo "changed_charts=" >changed_charts.txt
	echo "chart_version=" >chart_version.txt
	fi