Add docs from gofiber/fiber@8970f51

Author: github-actions[bot]

docs/core/middleware/cache.md

@@ -10,6 +10,31 @@ Request Directives<br />
 `Cache-Control: no-cache` will return the up-to-date response but still caches it. You will always get a `miss` cache status.<br />
 `Cache-Control: no-store` will refrain from caching. You will always get the up-to-date response.
 
+Cacheable Status Codes<br />
+
+This middleware caches responses with the following status codes according to RFC7231:
+
+- `200: OK`
+- `203: Non-Authoritative Information`
+- `204: No Content`
+- `206: Partial Content`
+- `300: Multiple Choices`
+- `301: Moved Permanently`
+- `404: Not Found`
+- `405: Method Not Allowed`
+- `410: Gone`
+- `414: URI Too Long`
+- `501: Not Implemented`
+
+Additionally, `418: I'm a teapot` is not originally cacheable but is cached by this middleware.
+If the status code is other than these, you will always get an `unreachable` cache status.
+
+For more information about cacheable status codes or RFC7231, please refer to the following resources:
+
+- [Cacheable - MDN Web Docs](https://developer.mozilla.org/en-US/docs/Glossary/Cacheable)
+
+- [RFC7231 - Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content](https://datatracker.ietf.org/doc/html/rfc7231)
+
 ## Signatures
 
 ```go

docs/core/whats_new.md

@@ -764,7 +764,8 @@ The adaptor middleware has been significantly optimized for performance and effi
 
 ### Cache
 
-We are excited to introduce a new option in our caching middleware: Cache Invalidator. This feature provides greater control over cache management, allowing you to define a custom conditions for invalidating cache entries.
+We are excited to introduce a new option in our caching middleware: Cache Invalidator. This feature provides greater control over cache management, allowing you to define a custom conditions for invalidating cache entries.  
+Additionally, the caching middleware has been optimized to avoid caching non-cacheable status codes, as defined by the [HTTP standards](https://datatracker.ietf.org/doc/html/rfc7231#section-6.1). This improvement enhances cache accuracy and reduces unnecessary cache storage usage.
 
 ### CORS