Automatically delete auxfiles and retry when needed

[chrisfenner]

Sometimes the cached aux files need to be deleted in order for rendering to succeed:

Rendering PDF
Latexmk: Sometimes, the -f option can be used to get latexmk
  to try to force complete processing.
  But normally, you will need to correct the file(s) that caused the
  error, and then rerun latexmk.
  In some cases, it is best to clean out generated files before rerunning
  latexmk after you've corrected the files.
PDF output failed
Elapsed time: 4 seconds
! Undefined control sequence.
l.1 \xpginauxfiletrue
                     
? 
! Emergency stop.
l.1 

The workaround is to delete the caches from actions/caches and re-run the workflow, but this isn't very user-friendly.

Future versions of the tool should automatically recover from this state.