Set default docs version to 0.26.0

RELNOTES: None.
PiperOrigin-RevId: 250578353
diff --git a/site/_config.yml b/site/_config.yml
index d0ae345..d060d72 100644
--- a/site/_config.yml
+++ b/site/_config.yml
@@ -11,7 +11,7 @@
 gems: [jekyll-paginate]
 
 # Update this to the newest release for the default docs.bazel.build version.
-version: "0.25.0"
+version: "0.26.0"
 
 # This must be kept in sync with //scripts/docs:doc_versions.bzl
 doc_versions: