Empty YAML object causes format deserialize to fail

[BernieWhite]

Description of the issue

When an empty object is passed to -InputObject when using the YAML input format (-Format Yaml) an exception is generated.

Consider:

---
metadata:
  name: anObject
---
# Commented out object
# metadata:
#   name: anObject2
---

To Reproduce

Steps to reproduce the issue:

Invoke-PSRule -InputObject (Get-Content -Path .\anObject.yaml -Raw | Out-String) -Format Yaml;

Expected behaviour

Empty objects should be ignored.

Error output

(Line: 10, Col: 4, Idx: 161) - (Line: 8, Col: 4, Idx: 161): Expected 'DocumentEnd', got 'Scalar' (at Line: 8, Col: 4, Idx: 161).

Module in use and version:

• Module: PSRule
• Version: 0.3.0-B190224

Captured output from $PSVersionTable:

Name                           Value
----                           -----
PSVersion                      5.1.17763.316
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.17763.316
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1