CI: Reduce macOS bins timeout to 31 minutes

37 minutes is a bit long. 31 minutes should allow most runs that are
*going* to finish to finish, without wasting more time than we need to
waiting for runs that are hung and are never going to finish anyway.

Considered 27, since *most* runs finish at 16 minutes, and all but one
of my ~11 test runs were under 27 minutes, but *one* of my test runs was
just under 31 minutes, so this should do the trick.

Having to wait for an entire additional run by being over-eager to retry
(too impatient) feels wasteful and not the best trade-off.

Anyhow, this is closer to the right number, even if picking a better
"exact ideal timeout" may be possible, this is close enough.

.github/workflows/build.yml

@@ -142,15 +142,15 @@ jobs:
         TEAM_ID: ${{ secrets.TEAM_ID }}
       uses: nick-fields/retry@7152eba30c6575329ac0576536151aca5a72780e
       with:
-        timeout_minutes: 37
+        timeout_minutes: 31
         max_attempts: 7
         command: yarn dist
 
     - name: Build Pulsar Binaries (macOS) (Unsigned)
       if: ${{ runner.os == 'macOS' && github.event_name != 'push' }}
       uses: nick-fields/retry@7152eba30c6575329ac0576536151aca5a72780e
       with:
-        timeout_minutes: 37
+        timeout_minutes: 31
         max_attempts: 7
         command: yarn dist