No binaries on PRs; to reduce PR CI times (#1621)

It takes a while to build them, and I suspect no-one is really using
them. After all, if you've been able to submit a PR, you can almost
certainly build the binaries yourself!

Author: noonio

.github/workflows/binaries.yaml

@@ -8,7 +8,6 @@ on:
     - release
     tags:
     - "*.*.*"
-  pull_request:
 
 jobs:
   # Produces static ELF binary for using MuslC which includes all needed