Add a task about archiving the previous year's rules

E.g: srobo/docs#349

Author: PeterJCLaw

kickstart/website/archive-previous-rules.yaml

@@ -0,0 +1,12 @@
+summary: Publish the rules for the previous year's game
+
+priority: major
+
+component: Website
+
+milestone: $SRYYYY Kickstart
+
+description: >-
+    Move the rules from the [rules](https://studentrobotics.org/docs/rules) page
+    to the [game archive](https://studentrobotics.org/docs/rules/archive) in the
+    docs, making way for the new rules to be published.

kickstart/website/publish-rules.yaml

@@ -11,8 +11,6 @@ description: >-
     The [rules](https://studentrobotics.org/docs/rules) page will need updating
     to show that the rules have been published and the link and image updating.
 
-    # We should also update the [//schools/game] page at the same time with
-    # a brief description of the game.
-
 dependencies:
     - kickstart/rules/write
+    - kickstart/website/archive-previous-rules