[tools] updating the version of verilator

### Description

We currently use verilator 4.210: https://github.com/lowRISC/opentitan/blob/f7ad56608cfcd9b62fa52bcf55c7f56560d613fe/doc/getting_started/setup_verilator.md. This version is released 2021-07-07.

The latest verilator version is now 5.038. The first version of v5 is v5.002, released 3 years ago (2022-10-29). We should aim to update our verilator to a more recent version.

Start with doc/getting_started/setup_verilator.md, which records the current Verilator 4.210 version and setup instructions. Determine a suitable recent Verilator 5.x version, update the documented version, and verify that the setup instructions work with it.

Written by the indexing model from the issue text.