exec: update simd-180 mainnet epoch

Author: emwang-jump

src/discof/replay/fd_exec.h

@@ -9,7 +9,7 @@
 
 /* FIXME: SIMD-0180 - set the correct epochs */
 #define FD_SIMD0180_ACTIVE_EPOCH_TESTNET (829)
-#define FD_SIMD0180_ACTIVE_EPOCH_MAINNET (5000)
+#define FD_SIMD0180_ACTIVE_EPOCH_MAINNET (841)
 
 /* Replay tile msg link formatting. The following take a pointer into
    a dcache region and formats it as a specific message type. */