fastbreak(cadence): upgrade

* Revert.
* Add grace period.

contracts/FastBreakV1.cdc

@@ -251,12 +251,20 @@ access(all) contract FastBreakV1: NonFungibleToken {
         /// Submit a Fast Break
         ///
         access(contract) fun submitFastBreak(submission: FastBreakV1.FastBreakSubmission) {
+            pre {
+                FastBreakV1.isValidSubmission(submissionDeadline: self.submissionDeadline) : "Submission missed deadline"
+            }
+
             self.submissions[submission.playerId] = submission
         }
 
         /// Update a Fast Break with new topshot moments
         ///
         access(contract) fun updateFastBreakTopshots(playerId: UInt64, topshotMoments: [UInt64]) {
+            pre {
+                FastBreakV1.isValidSubmission(submissionDeadline: self.submissionDeadline) : "Submission update missed deadline"
+            }
+
             let submission = &self.submissions[playerId] as &FastBreakV1.FastBreakSubmission?
                 ?? panic("Could not find submission for playerId: ".concat(playerId.toString()))
 
@@ -285,6 +293,12 @@ access(all) contract FastBreakV1: NonFungibleToken {
         }
     }
 
+    /// Validate Fast Break Submission
+    ///
+    access(all) view fun isValidSubmission(submissionDeadline: UInt64): Bool {
+        return submissionDeadline > UInt64(getCurrentBlock().timestamp) + 60
+    }
+
     /// Get a Fast Break Game by Id
     ///
     access(all) view fun getFastBreakGame(id: String): FastBreakV1.FastBreakGame? {