Reduce minimum size PDF requirement

README pdf is now very small!
5 jobs for master in 4 minutes and 43 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  .Pre
passed #510787
preflight

00:00:09

 
  Build
passed #510789
README.pdf

00:00:43

passed #510788
tex

00:03:37

 
  Test
passed #510791
test-pdfs

00:00:54

passed #510790
test-self

00:00:53