Relax `prop-types` to remove `fbjs` direct deps

[j0k3r]

The version of fbjs integrated to prop-types@15.5.10 was pretty old (^0.8.9, latest is 3.0.4) and was requiring an old version of isomorphic-fetch (^2.1.1) which integrate node-fetch "^1.0.1" which has 2 CVEs (one low and one high):

• https://github.com/advisories/GHSA-w7rc-rwvf-8q5r
• https://github.com/advisories/GHSA-r683-j2x4-v87g

I defined prop-types as ^15.6.2 which is the version where fbjs was removed. https://github.com/facebook/prop-types/blob/main/CHANGELOG.md#1562

[testshallpass]

Closing as I removed prop-types as a dependency in v5.0.0.