chore: update dependency of utils package

[novaliu86]

Update package isomorphic-fetch to new version. Get this when installing existing @0x/utils package:

$ npm audit
# npm audit report

node-fetch  <=2.6.6
Severity: high
node-fetch is vulnerable to Exposure of Sensitive Information to an Unauthorized Actor - https://github.com/advisories/GHSA-r683-j2x4-v87g
The `size` option isn't honored after following a redirect in node-fetch - https://github.com/advisories/GHSA-w7rc-rwvf-8q5r
No fix available
node_modules/node-fetch
  isomorphic-fetch  2.0.0 - 2.2.1
  Depends on vulnerable versions of node-fetch
  node_modules/isomorphic-fetch
    @0x/utils  *
    Depends on vulnerable versions of isomorphic-fetch
    node_modules/@0x/utils

3 high severity vulnerabilities

Some issues need review, and may require choosing
a different dependency.

Description

Testing instructions

Types of changes

Checklist:

• [ ] Prefix PR title with [WIP] if necessary.
• [ ] Add tests to cover changes as needed.
• [ ] Update documentation as needed.
• [ ] Add new entries to the relevant CHANGELOG.jsons.

[dekz]

added in #65