Add Package Including XXD to Package Dependencies

[apldev3]

In the course of setting up Docker for HIRS testing, I've run into an issue wherein the CentOS Docker Image doesn't include xxd by default, and since this makes use of it, it should be added as a dependency when packaging this project. A cursory glimpse as to packages that provide the xxd binary suggests that vim-common is the recommended one. Any other packages that supply it would also be acceptable.

[apldev3]

@iadgovuser29 was this deemed unimportant? Seems like a relatively small change to make.