Emulator no longer supports timelocking due to use of earlier protocol version

[catch-21]

Summary

Recent work on the emulator has causes a regression with transaction time validation support. It is no longer possible to check a transaction's time interval in plutus emluator.

@brunjlar located the bug in emulatorGlobals:

emulatorGlobals :: Globals
emulatorGlobals = mkShelleyGlobals
  genesisDefaultsWithBigMaxTxSize
  (fixedEpochInfo (EpochSize 432000) (mkSlotLength 8)) -- Not sure about these values, probably not relevant for the emulator.
  2 -- maxMajorPV

This sets a major protocol version of 2, but that has as a consequence that time handling will not work, because it only starts working with version 6.

Steps to reproduce the behavior

1. Build https://github.com/james-iohk/plutus-scripts/blob/78f5bd959b7bb94d022fb14906e2fb3c2d40d6f2/src/Deadline.hs
2. Load Deadline in repl and run runTrace
3. View output

Actual Result

Paying from script transaction is unsuccessful, script balance at end is 2ada

See error:

Slot 00002: *** CONTRACT STOPPED WITH ERROR: "\"WalletContractError (ValidationError (ScriptFailure (EvaluationError [\\\"Interval(1000000000000,PosInf)\\\"] \\\"CekEvaluationFailure\\\")))\""

Expected Result

Paying from script transaction is successful, script balance at end is 0.
No script validation errors seen.

Describe the approach you would take to fix this

Upgrade emulator from protocol version 2 to 6

System info

plutus-apps: 50290ad

[catch-21]

Verified this issue no longer exists on branch #455