Recommended Content Security Policy doesn't match Google's documentation #184

The GA4 documentation at https://developers.google.com/tag-platform/security/guides/csp suggests a different Content Security Policy than the README file at https://github.com/digital-analytics-program/gov-wide-code/blob/master/README.md#content-security-policy

As an implementer of DAP, I'd like to have consistent information about how to configure my system so that my analytics data will reliably be recorded.