wikiman: fix pacman.yaml linting

Add additional indenting in pacman.yaml lists
so that they will pass linting in the future.

Note this commit does not include an updated
pacman.yaml because this would also result in updating the
specific commit hash named artefacts

Author: tarrow

sync/wikiman/wikiman.py

@@ -54,6 +54,12 @@ def make_artifact_entry(details: Dict[str, str], extra_remove: List[str]) -> Dic
     }
     return entry
 
+# pylint: disable=too-many-ancestors
+class FixedIndentingDumper(yaml.Dumper):
+    """Fix for making yaml list output pass linting https://stackoverflow.com/a/39681672"""
+    def increase_indent(self, flow=False, indentless=False):
+        return super().increase_indent(flow, False)
+
 default_branch = get_mediawiki_branch_from_version(mediawiki_version)
 remove_from_all = codebases.get('removeFromAll', [])
 output: List[Dict] = [make_artifact_entry({
@@ -76,4 +82,4 @@ def make_artifact_entry(details: Dict[str, str], extra_remove: List[str]) -> Dic
 
 # write out to the lock.yaml file
 with open(DESTINATION_YAMLFILE, 'w') as outfile:
-    yaml.dump(output, outfile, sort_keys=False)
+    yaml.dump(output, outfile, sort_keys=False, Dumper=FixedIndentingDumper, default_flow_style=False)