updating getFeeHistory input type

[luu-alex]

Description

From the issue: #4510
Changing the paramters for getFeeHistory to comply with the spec:
input parameter should be formatted as hex not number
https://playground.open-rpc.org/?schemaUrl=https://raw.githubusercontent.com/ethereum/eth1.0-apis/assembled-spec/openrpc.json&uiSchema%5BappBar%5D%5Bui:splitView%5D=true&uiSchema%5BappBar%5D%5Bui:input%5D=false&uiSchema%5BappBar%5D%5Bui:examplesDropdown%5D=false

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• I have selected the correct base branch.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• Any dependent changes have been merged and published in downstream modules.
• I ran npm run dtslint with success and extended the tests and types if necessary.
• I ran npm run test:unit with success.
• I ran npm run test:cov and my test cases cover all the lines and branches of the added code.
• I ran npm run build and tested dist/web3.min.js in a browser.
• I have tested my code on the live network.
• I have checked the Deploy Preview and it looks correct.
• I have updated the CHANGELOG.md file in the root folder.

[render]

Your Render PR Server URL is https://web3-js-pr-4529.onrender.com.

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[coveralls]

Pull Request Test Coverage Report for Build 1463257976

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 72.548%

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Totals
Change from base Build 1442485720:	0.0%
Covered Lines:	3359
Relevant Lines:	4372

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💛 - Coveralls