Update Credits of Fractions sims

[Denz1994]

Related to #29.

Does a GitHub issue exist for tracking credits, to ensure that they are correct before publication?

All fractions-commmon related sims need their credits updated. I'm creating this issue to track this.

[jonathanolson]

@amanda-phet or @ariel-phet what should the credits be for the main 4 sims? Also do credits need to change for fraction-matcher at all?

[amanda-phet]

QA credits will need to be added for fraction-matcher but otherwise they can stay the same. (@KatieWoe should communicate QA credits for all sims after all testing is done.)

Fractions-Intro
Ariel Paul (lead designer)
Jonathan Olson (developer)
Sam Reid (original developer)
Mike Dubson
Trish Loeblein
Amanda McGarry
Kathy Perkins

Fractions-Mixed-Numbers
Amanda McGarry (lead designer)
Jonathan Olson (developer)
Sam Reid (original developer)
Mike Dubson
Trish Loeblein
Ariel Paul
Kathy Perkins

Fractions-Equality
Ariel Paul (lead designer)
Jonathan Olson (developer)
Sam Reid (original developer)
Mike Dubson
Trish Loeblein
Amanda McGarry
Kathy Perkins

Build-a-Fraction
Ariel Paul (lead designer)
Jonathan Olson (developer)
Sam Reid (original developer)
Mike Dubson
Karina K. R. Hensberry
Trish Loeblein
Amanda McGarry
Kathy Perkins

[ariel-phet]

@jonathanolson is also adding @veillette and some of his students where appropriate.

[jonathanolson]

Adjusted the credits above, I believe (besides QA) that they should be good.

[jonathanolson]

Assigning to QA so this can be added before publication.

[KatieWoe]

QA for all add (if not there already): Steele Dalton, Megan Lai, Liam Mulhall, Laura Rea, Jacob Romero, Katie Woessner, and Kelly Wurtz

[jonathanolson]

QA credits fixes pushed, applied to release branches, and deployed.