Feature flag console log warning links to old branch name

[connorshea]

https://link.vuejs.org/feature-flags is used here:

core/packages/runtime-core/src/featureFlags.ts

Line 36 in 079010a

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And it's still redirecting to the master branch, which causes a further redirect by github. Might be a good idea to update this URL redirect on vue's website to point to main.