Switch to yaml.safe_load (ros#21069)

Re: https://msg.pyyaml.org/load

scripts/check_rosdep.py

@@ -135,7 +135,7 @@ def fun(i, l, o):
  prev = st[lvl]
  try:
  # parse as yaml to parse `"foo bar"` as string 'foo bar' not string '"foo bar"'
- item = yaml.load(m.groups()[0])
+ item = yaml.safe_load(m.groups()[0])
  except:
  print('woops line %d' % i)
  raise
@@ -160,7 +160,7 @@ def my_assert(val):
  # here be tests.
  ydict = None
  try:
- ydict = yaml.load(buf)
+ ydict = yaml.safe_load(buf)
  except Exception:
  pass
  if ydict != {}:
@@ -176,7 +176,7 @@ def my_assert(val):
  else:
  print_test("skipping file with empty dict contents...")
  try:
- ydict = yaml.load(buf)
+ ydict = yaml.safe_load(buf)
 
  # ensure that values don't contain whitespaces
  whitespace_whitelist = ["el capitan", "mountain lion"]