LONDON (Reuters) -Britain is not ruling out sanctions targetted at Kremlin chief Vladimir Putin in person if Russia invades Ukraine, Foreign Secretary Liz Truss said on Wednesday. U.S. President Joe Biden said on Tuesday he would consider personal sanctions on Putin if Russia invades Ukraine, as Western leaders stepped up military preparations and made plans to shield Europe from a potential energy supply shock. Russia has massed more than 100,000 troops around Ukraine and the West fears it may invade in an attempt to annex its former Soviet republic. Asked about possible sanctions on Putin, T…