Start 1.0.0 section in the README

Author: seancorfield

README.md

@@ -327,6 +327,8 @@ only `parse-opts` and `summarize` were available.
 
 ## Change Log
 
+* Release 1.0.0 in progress
+  * Document the `:missing` option [TCLI-95](http://clojure.atlassian.net/browse/TCLI-95).
 * Release 0.4.2 2019-03-26
   * Restore ClojureScript compatibility (Martin Klepsch)
     [TCLI-94](http://clojure.atlassian.net/browse/TCLI-94).