v2.6.6

Changes:

• #94: Turns off preview tag on 2.x tasks.
• #92: Adds TlsHelper from Azure-Pipelines-Tasks to fix TLS 1.2 issues
• #89: Patches Get-TFSClientCredentials to force-load newtonsoft.json.
• #85: Refresh the workspace cache
• #83: Features/sdk upgrade
• #55: Cannot bind argument to parameter 'Name' because it is null
• #46: unsupported characters ń

This list of changes was auto generated.