This allows the script to be able to be used with
test networks more easily.

Usage:

```bash
export L1_RPC=...
export PRIVATE_KEY_DEPLOYER=0x...

npx hardhat deposit-eth \
    --l2-provider-url ... \
    --to 0x9C822C992b56A3bd35d16A089d99AEc870eF8d37 \
    --amount 0.0001 \
    --network final-migration-rehearsal
```

The following transactions were created using this commit
on the `final-migration-rehearsal` network:

L1 Deposit Transaction hash: 0x23f42a9d18b41bd32d90026b2324dbab64a45e942fe3897dd67a56989b940e11

L2 Withdrawing Transaction hash: 0x5b1108b61b7ec97f99c3c5c312913d465e87feaec2ab805087be55d342d5e17d

L1 Proving Withdrawal Transaction hash: 0xfe8c8beae69bdca1af35f04cfa635ea7d959abf0270f082a4ab41d680d7fe35b

L1 Finalizing Withdrawal Transaction hash: 0xcab6550b4a388e0c6fbb4b3e1604b42e2ca228aed8c5a1a8601e596f4a939e56