SECTION 1. Commonwealth Act Numbered Four hundred and forty-four, otherwise known as the Eight Hour Labor Law, is amended by inserting a new section under section seven of the said Act, which shall be known as section seven-A, to read as follows:
"SEC. 7-A. Any action to enforce any cause of action under this Act shall be commenced within three years after the cause of action accrued, otherwise such action shall be forever barred: Provided, however, That actions already commenced before the effective date of this Act shall not be affected by the period herein prescribed."