chore: pin rxjs to 6.6.3 to match sourcegraph/sourcegraph

[chrismwendt]

cc @sourcegraph/frontend-devs

[codecov]

Codecov Report

Merging #408 (c49dd20) into master (a7aa682) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #408   +/-   ##
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  Coverage   85.91%   85.91%           
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  Files          14       14           
  Lines         653      653           
  Branches      175      175           
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  Hits          561      561           
  Misses         92       92           

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[eseliger]

If this version match is important, should we make it a peer dependency instead?

[chrismwendt]

It sounds like peer dependencies aren't very ergonomic to work with: https://dev.to/yvonnickfrin/how-to-handle-peer-dependencies-when-developing-modules-18fa

Do you have enough knowledge about peer dependencies to recommend them? I'm vaguely familiar with the concept, but I don't know all the quirks.

[eseliger]

I haven't used them much in dev, only found them handy when some package I depend on requires React for example, that it'll always use the version I provide and not bundle a second one.

[chrismwendt]

I'm hesitant to use peer deps because I'm not sure how we can make sure it does what we expect in different scenarios:

• Running tests (needs the dep)
• yarn link in sourcegraph/sourcegraph (should not have the dep)

I can imagine juggling that being confusing/annoying. Keeping the version in sync with sourcegraph/sourcegraph seems more straightforward in my mind right now, but I'm not opposed to trying peer deps sometime.

[eseliger]

I think a devDependency could fix the testing part. Not worth breaking a sweat rn though.

[chrismwendt]

I wonder what would happen if you used a devDependency and then yarn link into sourcegraph/sourcegraph. I'm guessing rxjs would be present when it shouldn't, but I don't know for sure.