v2.8.6

• keeptitle attribute to retain provided title text: metanorma/metanorma-iso#1124
• Support figure/@width attributes: metanorma/metanorma-iso#1111
• Deduplicate class attributes between multiple instances of SVG: metanorma/metanorma#359
• Indicate which bibdata/docidentifier is primary, for downstream consumers of bibdata: metanorma/metanorma#361
• Add label attribute on cross-references, to customise the label for the kind of entity the cross-reference is pointing to: metanorma/metanorma-iso#1141