+1
I had the same squeak, tried WD40 and only worked for a day or 2, got a spray can of white silicon grease and it's been silent ever since.
Took about 3/4 applications once a week, basically position yourself so your head is looking up under the pedals (not easy especially when you are 6'4") and if you move the clutch pedal by hand you will see the offending spring, mine squeaked at about half way, just spay a decent amount of the grease on and manipulate it a bit
As I said after about 3/4 goes it has been silent since, for about a year near enough....