Bump cross-fetch to version 4

[rdvorkin]

Fixes issues like lquixada/cross-fetch#78, enabling to run web3.js in service worker

[codecov]

Codecov Report

Merging #6463 (90f5151) into 4.x (4b445ae) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##              4.x    #6463   +/-   ##
=======================================
  Coverage   89.39%   89.39%           
=======================================
  Files         212      212           
  Lines        8137     8137           
  Branches     2213     2213           
=======================================
  Hits         7274     7274           
  Misses        863      863           

Flag	Coverage Δ
UnitTests	89.39% <ø> (ø)

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Components	Coverage Δ
web3	∅ <ø> (∅)
web3-core	∅ <ø> (∅)
web3-errors	∅ <ø> (∅)
web3-eth	∅ <ø> (∅)
web3-eth-abi	∅ <ø> (∅)
web3-eth-accounts	∅ <ø> (∅)
web3-eth-contract	∅ <ø> (∅)
web3-eth-ens	∅ <ø> (∅)
web3-eth-iban	∅ <ø> (∅)
web3-eth-personal	∅ <ø> (∅)
web3-net	∅ <ø> (∅)
web3-providers-http	∅ <ø> (∅)
web3-providers-ipc	∅ <ø> (∅)
web3-providers-ws	∅ <ø> (∅)
web3-rpc-methods	∅ <ø> (∅)
web3-utils	∅ <ø> (∅)
web3-validator	∅ <ø> (∅)

[luu-alex]

Changelog needs to be updated

[jdevcs]

lgtm, update changelog as mentioned by Alex

[Muhammad-Altabba]

Thanks @rdvorkin,
I also updated the CHANGELOG.md file