Adjust constructor Null safety

1. cloudinary_url_gen
2. adjust
3. Adjust
4. Adjust constructor

Adjust class

1. Constructors
2. Adjust
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Static methods
12. autoBrightness
13. autoColor
14. autoContrast
15. blue
16. brightness
17. brightnessHSB
18. contrast
19. fillLight
20. gamma
21. green
22. hue
23. improve
24. opacity
25. opacityThreshold
26. recolor
27. red
28. replaceColor
29. saturation
30. sharpen
31. tint
32. unsharpMask
33. vibrance
34. viesusCorrect