remove extra column from table

TESTNET.md

@@ -55,7 +55,7 @@ The MobileCoin ledger will be reset at the end of each TestNet period to accommo
 During normal service hours our goal will be to maintain 100% uptime. We plan to rehearse enclave updates that will cause service interruption during *Maintenance Hours*.
 
 |Period | Start Date | End Date | Maintenance Hours |
-| -- | -- | -- | -- | -- |
+| -- | -- | -- | -- |
 | 1 | Wed Apr 22 | Wed Apr 29 |  Daily 5PM-10PM PST |
 | 2 | Wed Apr 29 | Wed May 13 |  M-F 5PM-7PM PST |
 | 3 | Wed May 13 | (TBD) | M,W,F 5PM-6PM PST |