Fix Eth:Tx.decode for transaction with s length < 64 chars

[Regul777]

Sometimes transaction can have "s" that has 62 char length, instead of 64 chars.

In the "ethereumjs-monorepo"(which is used in web3.js) used the same solution for creation signature
https://github.com/ethereumjs/ethereumjs-monorepo/blob/f39b0b2c826031a3f56b30f154d80c85bebfd611/packages/util/src/signature.ts#L59

const signature = Buffer.concat([setLengthLeft(r, 32), setLengthLeft(s, 32)], 64)

I've added the example transaction in tests:

Raw Transaction:
0xf86b820e8485012a05f200831e848094ffe811714ab35360b67ee195ace7c10d93f89d8c80844e71d92d8194a07b8f34a8fb85d850b3be4fc0330382e125e4216df5598c6d2c3bc47954684cf99f35ef53ee007c2f705eca91448b5c86e81d10f659ad868409bac8197bba9814

[codecov-commenter]

Codecov Report

Merging #148 (8368df0) into main (c100d53) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #148   +/-   ##
=======================================
  Coverage   99.74%   99.74%           
=======================================
  Files          67       67           
  Lines        3901     3911   +10     
=======================================
+ Hits         3891     3901   +10     
  Misses         10       10           

Impacted Files	Coverage Δ
lib/eth/tx/legacy.rb	100.00% <100.00%> (ø)
spec/eth/tx_spec.rb	100.00% <100.00%> (ø)

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[q9f]

fix looks good, we would need to apply to for all transaction types though!

also, please run rufo on the code!