Update GitHub pull request builder plugin

- Update docs of options to have default
- Fix merge-comment option to be type str
- Update convert_mapping_to_xml to use fail_required=True argument

Change-Id: I018219d80e0c54c951ef79fb4ca1bb53f0b63497
Signed-off-by: Kien Ha <kienha9922@gmail.com>

jenkins_jobs/modules/publishers.py

@@ -6259,7 +6259,7 @@ def github_pull_request_merge(parser, xml_parent, data):
     :arg bool disallow-own-code: if `true` will allow merging your own pull
         requests, in opposite to needing someone else to trigger the merge.
         (default false)
-    :arg bool merge-comment: Comment to set on the merge commit (optional)
+    :arg str merge-comment: Comment to set on the merge commit (default '')
     :arg bool fail-on-non-merge: fail the job if the merge was unsuccessful
         (default false)
     :arg bool delete-on-merge: Delete the branch of the pull request on
@@ -6284,12 +6284,12 @@ def github_pull_request_merge(parser, xml_parent, data):
         # option, xml name, default value
         ("only-admins-merge", 'onlyAdminsMerge', 'false'),
         ("disallow-own-code", 'disallowOwnCode', 'false'),
-        ("merge-comment", 'mergeComment', None),
+        ("merge-comment", 'mergeComment', ''),
         ("fail-on-non-merge", 'failOnNonMerge', 'false'),
         ("delete-on-merge", 'deleteOnMerge', 'false'),
     ]
 
-    helpers.convert_mapping_to_xml(osb, data, mapping)
+    helpers.convert_mapping_to_xml(osb, data, mapping, fail_required=True)
 
 
 class Publishers(jenkins_jobs.modules.base.Base):

tests/publishers/fixtures/github-pull-request-merge002.xml

@@ -4,6 +4,7 @@
     <org.jenkinsci.plugins.ghprb.GhprbPullRequestMerge>
       <onlyAdminsMerge>false</onlyAdminsMerge>
       <disallowOwnCode>false</disallowOwnCode>
+      <mergeComment/>
       <failOnNonMerge>false</failOnNonMerge>
       <deleteOnMerge>false</deleteOnMerge>
     </org.jenkinsci.plugins.ghprb.GhprbPullRequestMerge>