docs: update CONTRIBUTING.md

Revert #47

Cache is introduced by #120

CONTRIBUTING.md

@@ -2,6 +2,24 @@
 
 ## Add the packages
 
-Please update [registry.yaml](registry.yaml).
+Please update [aqua.yaml](aqua.yaml) and [registry.yaml](registry.yaml).
+aqua.yaml is used to test registry.yaml in CI.
 
 Packages are sorted in the dictionary order of the package name.
+
+In aqua.yaml, please add the code comment to update tools with [Renovate's Regex Manager](https://docs.renovatebot.com/modules/manager/regex/).
+
+e.g.
+
+```yaml
+- name: terraform
+  registry: standard
+  version: v1.0.6 # renovate: depName=hashicorp/terraform
+```
+
+CI is run on Linux, so it is difficult to test if the registry works well in Mac OSX.
+If you use Max OSX, please check if the registry works well in your localhost.
+
+```
+$ aqua i --test
+```