input: Write a function to filter words that start with a vowel.
  assert filter_words_with_vowel(["apple", "banana", "orange", "umbrella", "grape"]) == ["apple", "orange", "umbrella"]
  assert filter_words_with_vowel(["dog", "elephant", "iguana", "octopus", "unicorn"]) == ["elephant", "iguana", "octopus", "unicorn"]
  assert filter_words_with_vowel(["car", "bike", "airplane", "eagle", "owl"]) == ["airplane", "eagle", "owl"]
output: def filter_words_with_vowel(words):
      vowels = 'aeiouAEIOU'
      return [word for word in words if word[0] in vowels]