chore: release 0.26.0 (#2355)

Release-As: 0.26.0

Author: Yuan325

.hugo/hugo.toml

@@ -51,6 +51,10 @@ ignoreFiles = ["quickstart/shared", "quickstart/python", "quickstart/js", "quick
 # Add a new version block here before every release
 # The order of versions in this file is mirrored into the dropdown
 
+[[params.versions]]
+  version = "v0.26.0"
+  url = "https://googleapis.github.io/genai-toolbox/v0.26.0/"
+
 [[params.versions]]
   version = "v0.25.0"
   url = "https://googleapis.github.io/genai-toolbox/v0.25.0/"