Fix link label in signpost.md

Author: eregon

docs-source/signpost.md

@@ -3,7 +3,7 @@
 Pick a `concurrent-ruby` version:
 
 * [master](./master/index.html)
-* [1.2.0 with edge 0.7.0](./1.2.3/index.html)
+* [1.2.3 with edge 0.7.0](./1.2.3/index.html)
 * [1.1.10 with edge 0.6.0](./1.1.10/index.html)
 * [1.1.9 with edge 0.6.0](./1.1.9/index.html)
 * [1.1.8 with edge 0.6.0](./1.1.8/index.html)