Typos in theduckcow.com tutorial

[Andrej730]

Was following tutorial mentioned in readme and it has some typos resulting in errors (which already fixed in https://github.com/CGCookie/blender-addon-updater/blob/master/__init__.py#L83).

Typos:

Traceback:

Error: Python: Traceback (most recent call last):
  File "addon_updater_ops.py", line 259, in execute
    months=settings.updater_interval_months,
AttributeError: 'BIM_ADDON_preferences' object has no attribute 'updater_interval_months'. Did you mean: 'updater_intrval_months'?

And there are some other erros like defining props with auto_check_update = bpy.props.BoolProperty instead of auto_check_update: bpy.props.BoolProperty which results in other errors if you attempt to update the addon:

Error: Python: Traceback (most recent call last):
  File "\addon_updater_ops.py", line 257, in execute
    updater.set_check_interval(
  File "\addon_updater.py", line 558, in set_check_interval
    raise ValueError("Enable must be a boolean value")
ValueError: Enable must be a boolean value

rna_uiItemR: property not found: BIM_ADDON_preferences.auto_check_update