upgrade flat-cache to 6.1.7

[supdann]

This PR updates flat-cache to remove the outdated [email protected].

By upgrading flat-cache, all dependencies now use [email protected], aligning it with the rest of the project.

Changes Made:

• Updated flat-cache in package.json
• Regenerated yarn.lock to ensure the correct dependency tree
• Modified plugin.ts if necessary to ensure compatibility with the updated package API & breaking changes.

Testing & Validation:

Verified using pnpm why glob now shows only [email protected]
Ran pnpm install successfully with no warnings
Made sure to apply the breaking changes according to the flat-cache docs.
The result of running v4 & v5 tests:

[minecrawler]

@hipstersmoothie will we ever get this? It's kinda sad to see nextjs+storybook always throw warnings on every single npm install... not to forget security fixes, as others lined out.