fix: 🐛 node-fetch: request is not a function

[hzz780]

1. Close Bug: node-fetch, request is not a function #173

[vizipi]

Pull request analysis by VIZIPI

Below you will find who is the most qualified team member to review your code.
This analysis includes his/her work on the code included in this Pull request, in addition to their experience in code affected by these changes ( partly found within the list of potential missing files below )   Feedback always welcome

Reviewers with knowledge related to these changes

Match %	Person	Commit Count	Common Files
100.00%	AbigailDeng	112	2
50.00%	potter-sun	8	1
50.00%	Alef-hz	5	1

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Potential missing files from this Pull request

files commonly committed with a subset of this pr, but not committed this time. (click to collapse)

File	Percentile	rate
yarn.lock	77.78%	7 out of 9 times
dist/aelf.cjs.js	77.78%	7 out of 9 times
dist/aelf.umd.js	77.78%	7 out of 9 times
dist/aelf.cjs.js.map	77.78%	7 out of 9 times
dist/aelf.umd.js.map	77.78%	7 out of 9 times
src/util/proto.js	66.67%	6 out of 9 times
src/util/utils.js	55.56%	5 out of 9 times
README.md	55.56%	5 out of 9 times
test/e2e/wallet.test.js	44.44%	4 out of 9 times
src/contract/contractMethod.js	44.44%	4 out of 9 times

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Committed file ranks

(click to expand)

99.64%[package.json]

74.02%[build/webpack.node.js]