World leaders ratcheted up pressure on Sunday on Russia for its war against Ukraine, with Ukrainian President Volodymyr Zelenskyy at the centre of a swirl of diplomacy on the final day of the Group of Seven summit of rich-world democracies. Zelenskyy's in-person attendance at one of the world's premier diplomatic gatherings is meant to galvanise attention on his nation's 15-month fight against Russia. Even before he landed on Saturday on a French plane, the G7 nations had unveiled a slew of new sanctions and other measures meant to punish Moscow and hamper its war-fighting abilities. Ukraine is the overwhelming focus…