height for input-group

Hi, I noticed the height was slightly off for fields in an input-group, here's my fix for the single only:

	.input-group {
		$height: ($input-font-size + $form-spacing * 1.5);
	
		.select2-container--foundation {
	
			.select2-selection--single,
			.selection .select2-selection--single {
				height: $height;
	
				.select2-selection__arrow {
					height: $height;
				}
			}
		}
	}