docs: add peterdudfield as a contributor for code

[allcontributors[bot]]

Adds @peterdudfield as a contributor for code.

This was requested by peterdudfield in this comment

[skip ci]

[peterdudfield]

@all-contributors please add @thomasarmstrong98 for code

[allcontributors[bot]]

@peterdudfield

@thomasarmstrong98 already contributed before to code