Regex change uppercase to lowercase in anchor tag href

I want any regex expression where can change all Uppercase to lowercase in href attribute in anchor tag.

For example:

<a href="/Category">Text</a>
<a href="/Abc-XYZ">Text</a>
<a href='/CategorY/'>Text</a>

Output should like:

<a href="/category">Text</a>
<a href="/abc-xyz">Text</a>
<a href='/category/'>Text</a>

I'm trying in Notepad++.