Update stable version.

Add new stable stein version and remove ocata.

Change-Id: I6bd0c65c51af89d8aa196185d95af24a43851e2a

_custom/custom.css

@@ -73,6 +73,7 @@
 .pike {background: #dfb;}
 .queens {background: #afd;}
 .rocky {background: #aee;}
+.stein {background: #ade;}
 .centos {background: #fef;}
 .baremetal {background: #eef;}
 .virtual {background: #efe;}

doc/source/index.rst

@@ -91,11 +91,6 @@ Linux (RHEL). These steps are marked as follows:
    Step that should only be run when choosing to use components from their
    stable branches rather than using packages/source based on current master.
 
-.. admonition:: Ocata
-   :class: ocata
-
-   Step that should only be run when installing from the Ocata stable branch.
-
 .. admonition:: Pike
    :class: pike
 
@@ -111,6 +106,11 @@ Linux (RHEL). These steps are marked as follows:
 
    Step that should only be run when installing from the Rocky stable branch.
 
+.. admonition:: Stein
+   :class: stein
+
+   Step that should only be run when installing from the Stein stable branch.
+
 .. admonition:: Validations
    :class: validations