Disabled trust for insecure environment

requests doesn't a bunch of weird things, including reading auth info
from your ~/.netrc file.  Disable that so our authorization header
doesn't get stomped.

src/mbed_cloud/client/client.py

@@ -37,6 +37,7 @@ def __init__(self, config):
         """
         self.config = config
         self.session = requests.Session()
+        self.session.trust_env = False
         self.session.headers.update(
             {
                 "Authorization": "Bearer %s" % self.config.api_key,