solidity-coverage version update

[kautukkundan]

What does this pull request do? Explain your changes. (required)

updated solidity-coverage version which supports the london upgrade mentioned in #457

Specific updates (required)

• updated solidity-coverage version to 0.7.17
• removed setting initial base fee to 0

How did you test each of these updates (required)

Does this pull request close any open issues?

Checklist:

• [ ] README and other documentation updated
• [ ] All tests using yarn test pass

[coveralls]

Pull Request Test Coverage Report for Build 1246976745

• 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 82.7%

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Totals
Change from base Build 1246965744:	0.0%
Covered Lines:	908
Relevant Lines:	1100

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💛 - Coveralls

[kautukkundan]

rebased from next after merging the CI fix