There is a way but it will get overwritten every time you update ATS itself.
Edit the administrator/components/com_ats/fof.xml file. Find the line
<option name="factoryClass">FOF30\Factory\BasicFactory</option>
Underneath that line type a new line with the contents
<option name="mediaVersion">YOUR_VALUE_HERE</option>
YOUR_VALUE_HERE is the media version query, i.e. what you see appended to all of ATS' CSS and JS files after the question mark. Changing that every time you make changes will effectively tell your users' browsers to skip the cached version of the file and reload it from your server.
FYI, when the mediaVersion configuration variable is not set in fof.xml our framework calculates it automatically based on the version of ATS currently installed and a unique value for your site (the $secret in your configuration.php). When you set this variable in fof.xml you override the default behavior.
Please note that the fof.xml file is part of ATS itself and it's overwritten every time you upgrade ATS. Therefore every time you upgrade ATS you'll have to do this change again.
Nicholas K. Dionysopoulos
Lead Developer and Director
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