add pptx for sixth video

[idilsezgin]

add pptx for sixth video for review.

[egekorkan]

Feedback:

• Basics slide can get some note text like "Let's start with basics"
• Slide 8: Reference can be also understood as the $ref keyword so we should use a different word in the slide and in the notes. I would say "validation keywords" fit the slideset the best.
• Slide 9: Type -> type AND restrict to a specific type
• Slide 11: unnecessary comma in notes
• Slide 15 has wrong code highlighting
• Slide 18: It would be good to have examples of 0 or 1 not accepted
• Slide 20: This one is advanced but let us explain it briefly. The contentMediaType keyword specifies the MIME type of the contents of a string, as described in RFC 2046. If you want to specify any type that is not JSON, it is possible to do this with contentMediaType keyword. The first one indicates a string containing an HTML document, encoded using the same encoding as the surrounding document: The second one indicates that a string contains a PNG image, encoded using Base64:

[egekorkan]

As discussed, the further review will happen when the videos are submitted. Merging