Fix skip_list definition for yamllint

It seems recent update of ansible-lint no longer allows us to use
top-level name but only accepts yaml[<name>] syntax to skip yaml lint
checks. This change updates the config file of ansible-lint to ensure
all yaml lint checks are skipped.

This also skips the experimental checks to skip a few errors currently
detected.

Depends-on: https://review.opendev.org/c/openstack/tripleo-ci/+/850893
Change-Id: Icac9f7c4d6501536467e286311dde34cc7cee198

.ansible-lint

@@ -8,17 +8,18 @@ skip_list:
   # TODO(zbr): Address in follow-ups
   - role-name
   - unnamed-task
-  # yaml ones:
-  - braces
-  - colons
-  - commas
-  - comments
-  - comments-indentation
-  - empty-lines
-  - indentation
-  - line-length
-  - new-line-at-end-of-file
-  - trailing-spaces
-  - truthy
-  - brackets
-  - hyphens
+  # yaml ones
+  - yaml[braces]
+  - yaml[colons]
+  - yaml[commas]
+  - yaml[comments]
+  - yaml[comments-indentation]
+  - yaml[empty-lines]
+  - yaml[indentation]
+  - yaml[line-length]
+  - yaml[new-line-at-end-of-file]
+  - yaml[trailing-spaces]
+  - yaml[truthy]
+  - yaml[brackets]
+  - yaml[hyphens]
+  - experimental