Added VOA300 linear optopcoupler

• Provide a URL to a datasheet for the symbol(s) you are contributing

https://mouser.com/pdfDocs/Vishay_VOA300_DS.pdf

• An example screenshot image is very helpful

• Ensure that the associated footprints match the official footprint library

Matches with either DIP-8 or DIP-8 smd variant, DIP-8 preselected.

• Check the output of the automated check scripts - fix any errors as required

 ~ check_symbol.py Isolator.kicad_sym -p VOA300
Checking symbol 'Isolator:VOA300':
 ~