LONDON (Reuters) -Britain’s pound headed for a second weekly rise and was close to a one-month high on Friday, helped by a large government spending package to support households that economists said should support the economy in the short term. The government on Thursday announced a 25% windfall tax on oil and gas producers’ profits to help fund a 15 billion pound ($18.9 billion) package of support for households struggling to meet soaring energy bills. Reaction on currency markets was muted, but analysts said signs of government support, which was mostly targeted at lower-income households, …