Here is the BPMN xml with escape characters as suggested by you
<camunda:connector>
<camunda:connectorId>http-connector</camunda:connectorId>
<camunda:inputOutput>
<camunda:inputParameter name=“url”>
https://www.my-dummy-service.com/my-api
</camunda:inputParameter>
<camunda:inputParameter name=“payload”>
[CDATA[execution.getVariable(‘myRequest’)]]
</camunda:inputParameter>
<camunda:inputParameter name=“method”>
POST
</camunda:inputParameter>
<camunda:inputParameter name=“headers”>
application/json
</camunda:inputParameter>
<camunda:outputParameter name=“isHoliday”>
<camunda:script scriptFormat=“Javascript” resource=“parseMyResponse.js” />
</camunda:outputParameter>
</camunda:inputOutput>
</camunda:connector>