Versions in same sandbox differently for different people

🐛 bug report

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Description of the problem

When dependencies have a version as a tag (like next) we expect that everyone will resolve to the same version, but because we cache the result of resolving the absolute version for the tag, people have sometimes run in the issue that one browser resolves a different version than the other browser. We should probably remove that caching so that everyone will always resolve the same absolute version for a tag.

How has this issue affected you? What are you trying to accomplish?

I've heard reports where people were debugging for hours ("It works on my machine!"), and finally found out that they resolved different versions. That's very frustrating, so I'd say that we should fix this soon.

To Reproduce

1. Open a sandbox with react@next, find the request that resolves next to an absolute version
2. Make sure that we don't cache that, either by changing our service worker settings in webpack.prod.js, or by changing the server logic so that we send no-cache headers.

Start by reproducing the react@next resolution request and inspect webpack.prod.js along with the server logic that handles the request. Check how the absolute version is cached and whether cache headers are involved. Done means different browsers resolve the tag to the same absolute version.