CLI version 2.3.1

Version 2.3.1 of the CLI fixes two bugs in the frontastic upload command:

• In certain scenarios, the command attempted to initiate the interactive creation of a configuration file. We have corrected this behavior because the command does not require a configuration file and should operate non-interactively, especially in continuous integration environments.
• Running the command without setting either the clientId or clientSecret environment variables failed and generated an ambiguous error message related to token retrieval from Studio. Now, the error message is clearer and states which variables are missing.