Replace isomorphic-fetch

[boray]

Fixes #1904

This PR replaces outdated isomorphic fetch with built-in fetch and updates the fetch examples to devnet from berkeley.

[mitschabaude]

Why do we need this instead of using built-in fetch?

[ymekuria]

Why do we need this instead of using built-in fetch?

I agree with @mitschabaude here. We should use the built-in fetch instead of adding a dependancy. We moved to node fetch in the zkApp-CLI as well.

[boray]

Why do we need this instead of using built-in fetch?

The main reason is to not drop support for node versions <18.

[mitschabaude]

Why do we need this instead of using built-in fetch?

The main reason is to not drop support for node versions <18.

I think we can do us a favor and drop that support!

[45930]

I think we should include a changelog entry for this, but otherwise LGTM!

[boray]

I think we should include a changelog entry for this, but otherwise LGTM!

You're right, we're dropping support for node versions <18 with the last commit, so this needs to be included in the changelog. Also, this breaks backward compatibility. Should we wait for v3 to release this PR?

[mitschabaude]

I'd consider it not breaking, and would release it under a patch version, because we have been explicit about not supporting node < 18 before:

• Our docs state that node >= 18 is required
• the "engine" field in o1js package.json has "node": ">=18.14.0"

[45930]

I suppose we need to be more explicit about our definition of breaking. I'm inclined to agree with Gregor that we are very explicit already about node 18+ being required. As we release major versions in the future, we may want to aggressively bump that supported node version so we can continue to make changes like these.

I'm ok to merge this in a minor version. Even though I see the argument that we're "dropping support", I don't think that we actually had previously "supported" those versions. They just happened to work.

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