Update CHANGELOG.md

CHANGELOG.md

@@ -15,6 +15,7 @@ Released: -
 * [Fixed] Replace `urldecode()` (deprecated RFC 1738) with `rawurldecode()`
           (RFC 3986) in `Page::evaluateRequestUrl()`
 * [Fixed] #272: Encode URLs using `rawurlencode()` in `Pico::getPageUrl()`
+* [Fixed] #274: Prevent double slashes in `base_url`
 ```
 
 ### Version 1.0.0-beta.1