chore(deps): make express an optional peer dependency

[benmccann]

Summary

closes #2814

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[salesforce-cla]

Thanks for the contribution! Before we can merge this, we need @benmccann to sign the Salesforce Inc. Contributor License Agreement.

[benmccann]

I have signed the CLA

[WilliamBergamin]

Hi @benmccann thanks for bringing this up 💯

We need to make express a required peer dependency, making it an optional peer dependency might be considered a breaking change for some users, once resolved we should be good to merge

[WilliamBergamin]

Since express is currently a dependency we can't make it an "optional" peerDependency since some users may be relying on it to transitively import express in their projects, this would cause a breaking change

Removing this section would make express a required peer-dependency (non-breaking change), this will allow users to explicitly exclude it from their projects with npm install --omit peer