README: use correct column name, update markdown code blocks
README: use correct column name, update markdown code blocks

benjaminwols/two_factor_authentication,alphagov/two_factor_authentication,Houdini/two_factor_authentication,dahal/two_factor_authentication,alphagov/two_factor_authentication,dahal/two_factor_authentication,fonji/two_factor_authentication_root,fonji/two_factor_authentication_root,Houdini/two_factor_authentication,benjaminwols/two_factor_authentication,benjaminwols/two_factor_authentication,monfresh/two_factor_authentication,monfresh/two_factor_authentication,alphagov/two_factor_authentication,fonji/two_factor_authentication_root,dahal/two_factor_authentication,Houdini/two_factor_authentication,monfresh/two_factor_authentication