`composerUpdateMax` and `composerUpdateMin` should return an error exit code if installation fails

[oliverklee]

Short problem description

When composerUpdate(Min|Max) from our runTests.sh fails (e.g., due to a repository not being reachable or the requirements creating unsolvable dependency problems), the process still returns a success return code. Then the next CI steps get executed and runs into problems because the Composer packages are not installed.

Steps to reproduce the problem

1. create unsolvable dependencies in composer.json, e.g. "php": "^5.6".
2. run ./Build/Scripts/runTests.sh -s composerUpdateMax
3. echo $? to show the exit code

actual behavior

Exit code 0

Also, composerUpdateMax continues to show the installed packages etc.

expected behavior

Exit code 1

Also, composerUpdateMax exits after the first problem as the next steps (show installed packages etc.) do not make sense anymore.

Additional Information

We also should port this fix to the TYPO3 Core.

Info on exit codes