Subsection (h) of section 13 of said chapter 17 , as appearing in section 3 of chapter 104 of the acts of 1979, is hereby amended by adding the following 2 paragraphs:- Any proposed lease, rental or other agreement to authorize the use of town property for a period exceeding 180 days shall be approved in advance by a three-fifths vote of the board of selectmen at a regularly scheduled public meeti