Your First Zenoh app examples don't work due to missing config

[mattvalentine]

The examples in Your first Zenoh app do not work with version eclipse-zenoh==1.0.0b2

Traceback (most recent call last):
  File "z_sensor.py", line 11, in <module>
    session = zenoh.open()
TypeError: open() missing 1 required positional argument: 'config'

Traceback (most recent call last):
  File "z_subscriber.py", line 11, in <module>
    session = zenoh.open()
TypeError: open() missing 1 required positional argument: 'config'

[mattvalentine]

I figured out how to get it to run, and made a small pr #67