Regular expressions do not work with flags

[jeromesimeon]

Bug Report 🐛

Regular expressions with flags e.g., /^[a-zA-Z0-1]*^/u do not work.

Expected Behavior

Regular expressions should work with flags.

Current Behavior

With the given CTO:

namespace org.test

concept Person {
	o String name regex=/^[a-zA-Z][a-zA-Z0-9]*$/u
	o Double age
}

And input data:

{
    "$class": "org.test.Person",
    "name": "John",
    "age": 33
}

The validation fails:

zsh-5.8$ concerto validate --model test.cto --input person.json
7:56:56 AM - INFO: Input is invalid
7:56:56 AM - ERROR: Validator error for field undefined org.test.Person.name: Value + 'John' failed to match validation regex: /^[a-zA-Z][a-zA-Z0-9]*$\//
Error: Validator error for field undefined org.test.Person.name: Value + 'John' failed to match validation regex: /^[a-zA-Z][a-zA-Z0-9]*$\//
    at StringValidator.reportError (/usr/local/lib/node_modules/@accordproject/concerto-cli/node_modules/@accordproject/concerto-core/lib/introspect/validator.js:44:15)
    at StringValidator.validate (/usr/local/lib/node_modules/@accordproject/concerto-cli/node_modules/@accordproject/concerto-core/lib/introspect/stringvalidator.js:56:22)
    at ResourceValidator.checkItem (/usr/local/lib/node_modules/@accordproject/concerto-cli/node_modules/@accordproject/concerto-core/lib/serializer/resourcevalidator.js:327:42)
    at ResourceValidator.visitField (/usr/local/lib/node_modules/@accordproject/concerto-cli/node_modules/@accordproject/concerto-core/lib/serializer/resourcevalidator.js:221:22)
    at ResourceValidator.visit (/usr/local/lib/node_modules/@accordproject/concerto-cli/node_modules/@accordproject/concerto-core/lib/serializer/resourcevalidator.js:77:25)
    at Field.accept (/usr/local/lib/node_modules/@accordproject/concerto-cli/node_modules/@accordproject/concerto-core/lib/introspect/decorated.js:65:24)
    at ResourceValidator.visitClassDeclaration (/usr/local/lib/node_modules/@accordproject/concerto-cli/node_modules/@accordproject/concerto-core/lib/serializer/resourcevalidator.js:174:26)
    at ResourceValidator.visit (/usr/local/lib/node_modules/@accordproject/concerto-cli/node_modules/@accordproject/concerto-core/lib/serializer/resourcevalidator.js:73:25)
    at ConceptDeclaration.accept (/usr/local/lib/node_modules/@accordproject/concerto-cli/node_modules/@accordproject/concerto-core/lib/introspect/decorated.js:65:24)
    at ValidatedResource.validate (/usr/local/lib/node_modules/@accordproject/concerto-cli/node_modules/@accordproject/concerto-core/lib/model/validatedresource.js:125:26)