The
href
attribute of the
a
tag is what should hold the address of your homepage. Plus, you didn't close the
img
tag properly:
<a href="https://path/to/your/homepage"><img src="https://i.imgur.com/YonN1NM.png?1" title="source: imgur.com" alt="{{$lang.project_name}}" id="logo-changer" /></a>