Security vulnerability: update isomorphic-fetch to latest

[daniel-liu-bitio]

Isomorphic-fetch 2.2.1 (the version currently being used) has a security vulnerability since it depends on an unsafe version of node-fetch. Running npm i @segment/consent-manager followed by npm audit gives:

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/@segment/consent-manager/node_modules/node-fetch
  isomorphic-fetch  2.0.0 - 2.2.1
  Depends on vulnerable versions of node-fetch
  node_modules/@segment/consent-manager/node_modules/isomorphic-fetch
    @segment/consent-manager  *
    Depends on vulnerable versions of isomorphic-fetch
    node_modules/@segment/consent-manager

This is fixed in subsequent versions of isomorphic-fetch (see matthew-andrews/isomorphic-fetch#189). Would it be possible to bump up the version of isomorphic-fetch for this package?