arduino-cli on OSX doesn't create arduino15 folder

[fabiopozzi]

I have downloaded the arduino-cli binary, installed in /usr/local/bin/.
When I run arduino-cli core update-index for the first time I get

Updating index: package_index.json downloaded
Error: open /Users/fabio/Library/arduino15/package_index.json: no such file or directory
Error saving downloaded index https://downloads.arduino.cc/packages/package_index.json

So I manually create the folder:

mkdir /Users/fabio/Library/arduino15

and the issue is solved.
I don't know if the documentation should indicate to the user to create the directory or the tool should create it.
I am willing to help patch the sources if the tool should create the directory.

[michelepagot]

DuplicaTe of issue 6#

[fabiopozzi]

I wonder if getDefaultArduinoDataDir() should create the directory if it doesn't exist or it should be created in NewConfiguration().

[sandeepmistry]

Closing as duplicate of #6.