chore: add api to the doc

SUPPORTED_APIS.md

@@ -41,6 +41,7 @@ The `status` options are:
 | `ANVIL` | `anvil_setBalance` | `SUPPORTED` | Modifies the balance of an account |
 | `ANVIL` | `anvil_setCode` | `SUPPORTED` | Sets the bytecode of a given account |
 | `ANVIL` | `anvil_setStorageAt` | `SUPPORTED` | Sets the storage value at a given key for a given account |
+| `ANVIL` | `anvil_setChainId` | `SUPPORTED` | Sets the chain id |
 | [`CONFIG`](#config-namespace) | [`config_getShowCalls`](#config_getshowcalls) | `SUPPORTED` | Gets the current value of `show_calls` that's originally set with `--show-calls` option |
 | [`CONFIG`](#config-namespace) | [`config_getShowOutputs`](#config_getshowoutputs) | `SUPPORTED` | Gets the current value of `show_outputs` that's originally set with `--show-outputs` option |
 | [`CONFIG`](#config-namespace) | [`config_getCurrentTimestamp`](#config_getcurrenttimestamp) | `SUPPORTED` | Gets the value of `current_timestamp` for the node |