Remove deprecated features, bump version to 6.0.0 (#5326)

* Bump version to 6.0.0.

* sender option is now required.

* Default of want_proxmox_nodes_ansible_host changed from true to false.

* username is now an alias of user, and no longer of workspace.

* Remove deprecated return values in favor of end_state.

* Remove debug option.

* Change default of ignore_volatile_options from true to false.

* gitlab_group must now always contain the full path.

* Change default of norc from false to ture.

* Remove deprecated property.

* Add PR URL.

* Adjust bitbucket unit tests.

* Adjust module_helper integration test.

tests/integration/targets/module_helper/tasks/mstate.yml

@@ -70,25 +70,9 @@
     a: 5
     b: foo
     c: bar
-    trigger_depr_attr: true
     state: both_x_a
   register: state5
 
-- ansible.builtin.set_fact:
-    vardict_gt29:
-      msg: >-
-        ModuleHelper.VarDict attribute is deprecated, use VarDict from the
-        ansible_collections.community.general.plugins.module_utils.mh.mixins.vars
-        module instead
-      version: 6.0.0
-      collection_name: community.general
-    vardict_29:
-      msg: >-
-        ModuleHelper.VarDict attribute is deprecated, use VarDict from the
-        ansible_collections.community.general.plugins.module_utils.mh.mixins.vars
-        module instead
-      version: 6.0.0
-
 - name: assert state5
   assert:
     that:
@@ -97,6 +81,3 @@
       - state5.c == "bar"
       - state5.result == "foobarfoobarfoobarfoobarfoobar"
       - state5 is changed
-      - vardict_depr in state5.deprecations
-  vars:
-    vardict_depr: '{{ (ansible_version.major == 2 and ansible_version.minor == 9) | ternary(vardict_29, vardict_gt29) }}'