Add missing DOIs for the paper

[catalamarti]

• 10.32614/cran.package.omock may be a valid DOI for title: omock: Creation of Mock Observational Medical Outc...
• 10.32614/cran.package.cdmconnector may be a valid DOI for title: CDMConnector: Connect to an OMOP Common Data Model
• 10.32614/rj-2011-002 may be a valid DOI for title: testthat: Get Started with Testing
• 10.32614/cran.package.patientprofiles may be a valid DOI for title: PatientProfiles: Identify Characteristics of Patie...
• 10.32614/cran.package.omopgenerics may be a valid DOI for title: omopgenerics: Methods and Classes for the OMOP Com...