Apple’s next-generation iPad will launch in the next three to four months, according to a new report. Citing sources in the supply chain, DigiTimes reports that various parts and component makers have started to deliver pieces to OEM contractors while ramping down production of iPad 2 components. The report claims that OEM production of the iPad 2 will remain at 14-15 million units during the fourth-quarter of 2011 but decline to between four…