feat: add invalidate_cache for @cached decorator

[biraj21]

What do these changes do?

This PR adds an invalidate_cache function to the aiocache library, allowing users to explicitly invalidate the cache of a function decorated with @cache. Users can call the method directly on the cached function object with the arguments that were used to generate the cache key. Usage:

await <function_name>.invalidate_cache(*args, **kwargs)

Are there changes in behavior for the user?

Yes, this new functionality provides users with a convenient way to manually invalidate the cache for specific arguments of a cached function, enhancing flexibility and control over cache management.

Related issue number

N/A

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes

[altairmn]

What's the progress on this feature? it'd be great to have cache invalidation. Otherwise, the workaround for this is very messy.

[Dreamsorcerer]

I'd prefer to avoid adding more hacks like this onto the old code. This should really wait for #625 to be completed, which may require the other tasks listed before it in the milestone: https://github.com/aio-libs/aiocache/milestone/8