Corrected Issues found with 0.15.0 AppVeyor updates

[Philo]

What You Are Seeing?

• The UploadArtifact has an incorrectly named parameter (-ArtifactType should be -Type)
• The UploadTestResults is still silently completing without displaying uploaded test data

What is Expected?

• UploadArtifact should upload with the type specified, however it will use the default "Auto" type at the moment
• UploadTestResults needs an additional name parameter set for the multipart-form-data request

What version of Cake are you using?

0.15.0

Are you running on a 32 or 64 bit system?

64 bit

What environment are you running on? Windows? Linux? Mac?

Windows

Are you running on a CI Server? If so, which one?

AppVeyor

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I will have a pull request incoming asap with these corrections.

[gep13]

@Philo can you hold off submitting a PR? This might need to a be hotfix, and to facilitate that PR, we will need to create a hotfix branch, which you can select as the destination for the PR.

[gep13]

@Philo can you target this branch? https://github.com/cake-build/cake/tree/hotfix/0.15.1

[Philo]

ok, will do