Bump ansible-lint version to 6.*

Add fqcn-builtins to the skip list for now, we will watch how the
discussion about this evolves and defer updating all code according to
that [0].

[0] https://github.com/ansible/ansible-lint/issues/2050



Signed-off-by: Dr. Jens Harbott <harbott@osism.tech>
Change-Id: I6dcdec4f029b87bad41530ad45d285909c8351f7

.ansible-lint

@@ -25,3 +25,6 @@ skip_list:
   - package-latest
   # Most files should not contain tabs
   - no-tabs
+  # NOTE(frickler): Agreed at Zed PTG not to use FQCN for builtin actions for now, due to
+  # conflicts with open patches and backports.
+  - fqcn-builtins

lint-requirements.txt

 ansible>=4,<6 # GPLv3
-ansible-lint>=4.2.0,!=4.3.0,<6.0.0 # MIT
+ansible-lint>=6.0.0,<7.0.0 # MIT
 bandit>=1.1.0 # Apache-2.0
 bashate>=0.5.1 # Apache-2.0
 doc8>=0.6.0 # Apache-2.0