Create a function GenerateSectionData in main.go that generates data for the following type:

```go
type Section struct {
	SectionID    string `json:"section_id"`
	CourseNumber string `json:"course_number"`
	Instructor   string `json:"course_instructor"`
	CourseTitle  string `json:"course_title"`
	CourseType   string `json:"course_type"`
}
```

The function should take a config argument of type Config 

It should generate a list of []string called instructor_names equal in length to the NumberOfInstructors member of config meeting the following requirements: 

1. Each member should be a unique string which is a concatentaion of a brianvoe/gofaker LastName, a comma and a random uppercase letter

It should generate a list of []Section  equal to the NumberOfSection member of config meeting the following requirements:

1. SectionID should be a unique random string of 5 digits
1. Course Number should be a unique string which is a random upper-case letter followed by 3 digits
1. Instructor should be a random selection form the instructor_names list
1. CourseTitle should be a brianvoe/gofaker BookTitle
1. CourseType should be a random member of the globally-defined course_type list