chore: increment the build number for the 0.9.12 rebuild

Artifacts on the draft predate the stale-progress-file fix (#67), which is the
one that actually cured the hang. Build number 31 -> 32.

Author: StuartCameronCode

app/pubspec.yaml

@@ -1,7 +1,7 @@
 name: vapourbox
 description: "Video processing and cleanup powered by VapourSynth"
 publish_to: 'none'
-version: 0.9.12+31
+version: 0.9.12+32
 
 environment:
   sdk: ^3.6.2