Add "lambast" and "lambasts" to UK English

[DimitriPapadopoulos]

Valid variant of "lambaste" according to these dictionaries:

• Oxford Learner's
• Cambridge
• Chambers
• Collins
• Merriam-Webster

In the last few years, it looks like "lambast" has become more common than "lambaste":

• https://books.google.com/ngrams/graph?content=lambast%2Clambaste&year_start=1800&year_end=2019&corpus=en-2019