update docs

Author: puredanger

Diff for: docs/clojure.tools.build.api.html

@@ -61,6 +61,7 @@
 Sources are merged in the order - :root, :user, :project, :extra.
 
 Options (note, paths resolved via *project-root*):
+  :dir     - directory root path, defaults to current directory
   :root    - dep source, default = :standard
   :user    - dep source, default = nil (for reproducibility, not included)
   :project - dep source, default = :standard ("./deps.edn")