rename file for redcap_dag_export()

[wibeasley]

@joundso, a few followups to #382. Will you please

1. rename "R/redcap-read-dag.R" to "R/redcap-dag-read.R". If anyone is reviewing the file in GitHub, I want it to be obvious that you did most of the work (like the logging export function Function to export logfile #383)
2. Add yourself to the DESCRIPTION file after Victor?
3. I've already added you & the function to NEWS.md

If that's a hassle, I'm happy to do this. Just send me your ORCID number so you're better identified.

[joundso]

@wibeasley Thank you very much for your work and please excuse me for not getting back to you in a while! Unfortunately I hardly get to code here at the moment. I hope that will change again soon. Thanks again for all "helping out"!