one more env to unset, to work around Xcode's bug (#52)
one more env to unset, to work around Xcode's bug (#52)

for more info see https://github.com/fastlane/fastlane/issues/6495 - they used almost the same set of envs as we, but had this one too
bitrise-io/steps-new-xcode-archive,bitrise-io/steps-new-xcode-archive,bitrise-io/steps-xcode-archive,bitrise-io/steps-xcode-archive