Allow for tolerance with "participantRef"

[yT0n1]

Some files from external sources might contain "participantRef" instead of "participantRefs".

The standard is unclear regarding this. See pages 322 and 364 in the standard. BPMN20.cmof and Semantic.xsd differ in that regard (https://www.omg.org/spec/BPMN/#docs-normative-supporting). Import should support both options, export should support "participantRef" to be compatible with eclipse and Signavio

[jan-ladleif]

Here's the relevant replacement snippet from another project of mine for the import:

// Preprocessing: Signavio exports <participantRef> elements instead of
// <participantRefs> (notice the missing 's'). The metamodel expects the s, though.
xml = xml.replace(/<(\/)?(bpmn2:|bpmn:)?participantRef>/g, '<$1$2participantRefs>');

[jan-ladleif]

This has been fixed in bpmn-moddle with bpmn-io/bpmn-moddle#60

We should just update and use the participantRef variant now. There are probably no models around that use the version with the s.