Bump version -> 0.31.2

bin/version

 #!/usr/bin/env bash
 
-VERSION="v0.31.1"
+VERSION="v0.31.2"
 
 # dynamically pull more interesting stuff from latest git commit
 HASH=$(git show-ref --head --hash=7 head)            # first 7 letters of hash should be enough; that's what GitHub uses