0.6.1

Full Changelog: 0.6.0...0.6.1

• Added support for PackageRequirements blocks in ShaderLab code (https://docs.unity3d.com/Manual/SL-PackageRequirements.html)
• Fixed a small bug in the printing of ColorMask in ShaderLabPrinter.
• Add newlines after program blocks in ShaderLabPrinter.