Fail on upload error

[fractalwrench]

Goal

Adds mazerunner scenarios to verify the changes within #150, which fails the build if a mapping file upload task was not successful.

Changeset

• Includes the implementation from Be aware of errors during mapping uploads #150
• Sets failOnUploadError to true by default
• Fails the build if an API key is empty, in addition to null, during an upload task
• If a build variant does not have obfuscation enabled via minifyEnabled and has not applied the DexGuard plugin, the previous behaviour was to create an upload task that failed as there would be no mapping file. This task will no longer be created.

Tests

• Added mazerunner steps which check the exit code of a script, and for running a script that is expected to exit with a non-zero exit code
• Created mazerunner scenarios where the build is expected to fail due to:
  • an empty API key
  • using the wrong endpoint
  • a missing mapping file
• Created mazerunner scenarios where the build is expected to pass due to:
  • Uploading in a default app, with an API key, mapping file, and correct endpoint specified
  • Deobfuscation being disabled, therefore the plugin would not need to upload any mapping files

[fractalwrench]

Thanks for the review comments @Cawllec - I've addressed the feedback.

[Cawllec]

LGTM