Short answer
As long as you serve it in the header or in a new external .js file, they won't skip it.
Long answer
Patrick Sexton from feedthebot.com explains it perfectly here:
Common caching issue
If you list your html and images to be cached for one year or some
other long time period, remember that this can mean if you make a
change to your pages they may not be seen by all users. This is
because the users will look to cached files rather than the live ones.
If you have file that you tweak occasionally (example - a CSS file)
you can overcome the cache issue by using URL fingerprinting.
URL fingerprinting
Getting a fresh (not cached) file resource is possible by having a
unique name. An example would be if our css file was named "main.css"
we could name it "main_1.css" instead. The next time we change it we
can call it "main_2.css". This is useful for files that change
occasionally.