title: Trigger `git prune` automatically on `git pull`?
body: <p>On my local copy of a company-wide repository (where I make lots of short-lived branches and <code>git rebase</code> very very often, and where many other people are also pushing short-lived branches to the <code>origin</code> I'm pulling from), I regularly have the following conversation with git.</p>
  
  <pre><code>(env)$ git pull
  remote: Counting objects: 382, done.
  remote: Compressing objects: 100% (247/247), done.
  remote: Total 382 (delta 182), reused 62 (delta 62), pack-reused 73
  Receiving objects: 100% (382/382), 228.63 KiB | 0 bytes/s, done.
  Resolving deltas: 100% (232/232), completed with 15 local objects.
  From github.com:anon/anony2
     aee962f..055a717  master     -&gt; origin/master
     [...]
  Auto packing the repository in background for optimum performance.
  See "git help gc" for manual housekeeping.
  error: The last gc run reported the following. Please correct the root cause
  and remove .git/gc.log.
  Automatic cleanup will not be performed until the file is removed.
  
  warning: There are too many unreachable loose objects; run 'git prune' to remove them.
  
  Updating aee962f..055a717
  Fast-forward
  Auto packing the repository in background for optimum performance.
  See "git help gc" for manual housekeeping.
  error: The last gc run reported the following. Please correct the root cause
  and remove .git/gc.log.
  Automatic cleanup will not be performed until the file is removed.
  
  warning: There are too many unreachable loose objects; run 'git prune' to remove them.
   [...]
   9 files changed, 128 insertions(+), 95 deletions(-)
  (env)$ git prune
  Checking connectivity: 772524, done.
  (env)$ rm .git/gc.log
  (env)$
  </code></pre>
  
  <p>```</p>
  
  <p>That is: I say <code>git pull</code>; git spews a bunch of stuff at me, helpfully including two commands I need to run; I run those commands; then I can continue with my work.</p>
  
  <p>It would be awesome if git would just <em>run those commands for me</em>, instead of forcing me to cut-and-paste them. I get that this wouldn't be the default behavior of <code>git pull</code>, but it seems like the sort of thing that probably exists as an option I could add to my <code>.gitconfig</code>. Does such a thing exist?</p>