Description

This PR connects the global --debug flag up to our logger. Now, if you pass in --debug you will get debug logs. It is false by default which results in INFO level logging and above (WARN, ERROR)

Changes

• Uses Viper library (same author from cobra) that allows us to bind the flags globally so we can access them anywhere in the code without passing debug flags through all of our functions.
• Adds a PersistentPreRun so that we initialise the logger before the rest of the code is run.
• Moves update check logic into commands.go so that it can utilise the logger. If left in main, it will use an uninitialised logger

Ref: #142