LONDON (Reuters) -A tanker of Russian gas arrived at a French port in Brittany on Saturday after dock workers in Britain refused to unload it in protest at Russia’s invasion of Ukraine. The Boris Vilkitsky docked at the port of Montoir-de-Bretagne. Greenpeace said in a statement that some activists had gone to the French port to protest against the boat’s arrival. The Guardian newspaper reported the vessel had been on its way to the Isle of Grain, in southeast England, with a consignment of liquefied natural gas for Centrica, the owner of British Gas. (Reporting by Kate Holton, Jonathan Saul a…