bump nim-eth to `cc6d88962e4a22170361b576534246bd57974d80`

[etan-status]

• port eth2_digest speedups to eth_hash
• hash compatibility fix
• Revert speedups
• Removed obsolete chunked rlpx message protocol extension
• Treat putting empty data in hexary trie as deleting data

[github-actions[bot]]

Unit Test Results

         9 files  ±0    1 334 suites  ±0   32m 46s :stopwatch: + 2m 22s   5 064 tests ±0    4 716 :heavy_check_mark: ±0  348 :zzz: ±0  0 :x: ±0  20 991 runs  ±0  20 587 :heavy_check_mark: ±0  404 :zzz: ±0  0 :x: ±0 

Results for commit 6c3534fc. ± Comparison against base commit 231c41ea.