message: op-chain-ops: base fee check
  Check that the L2 genesis block base fee per gas
  is not set to `nil`. If it is, it will cause a segfault
  in `op-geth` on startup after the migration.
  It is configured with the key: `"l2GenesisBlockBaseFeePerGas"`
diff: @@ -2,6 +2,7 @@ package genesis
  import (
  "bytes"
  + "errors"
  "fmt"
  "math/big"
  @@ -53,6 +54,10 @@ func MigrateDB(ldb ethdb.Database, config *DeployConfig, l1Block *types.Block, m
  }, nil
  }
  + if config.L2GenesisBlockBaseFeePerGas == nil {
  + return nil, errors.New("must configure L2 genesis block base fee per gas")
  + }
  +
  underlyingDB := state.NewDatabaseWithConfig(ldb, &trie.Config{
  Preimages: true,
  })
  