By Max Hunder and Madeline Chambers KYIV/BERLIN (Reuters) -Western allies pledged billions of dollars in new weapons for Ukraine on Thursday, but the big question of whether to send heavy tanks remained unanswered, with Berlin yet to signal whether it would lift a veto. Fearing winter will give Russian forces time to regroup and unleash a major attack, Ukraine is pushing for German-made Leopard battle tanks, which are held by an array of NATO nations but whose transfer to Ukraine requires Germany’s approval. A German government source said Berlin would lift its objections if Washington sends i…