cmd/gopherbot: remove NeedsDecision label on proposals

Fixes golang/go#31788

Change-Id: I775f706a154f3584c24b1bd2f4925cbc293f8740
Reviewed-on: https://go-review.googlesource.com/c/build/+/180925
Reviewed-by: Andrew Bonventre <andybons@golang.org>
diff --git a/cmd/gopherbot/gopherbot.go b/cmd/gopherbot/gopherbot.go
index 45ef734..98632ee 100644
--- a/cmd/gopherbot/gopherbot.go
+++ b/cmd/gopherbot/gopherbot.go
@@ -750,6 +750,13 @@
 				return err
 			}
 		}
+
+		// Remove NeedsDecision if exists
+		if gi.HasLabel("NeedsDecision") {
+			if err := b.removeLabel(ctx, gi, "NeedsDecision"); err != nil {
+				return err
+			}
+		}
 		return nil
 	})
 }