Apple has unveiled a new range of iPads including a more powerful – and more expensive – Pro series that appears to be setting the increasingly feature-rich tablets up to rival Apple’s own Mac computers. The next iPad Pro is the first Apple device with the M4 chip, which is more focussed on apps using AI. The new models also come with an OLED screens for inkier blacks, and the version with a 13-inch display is the thinnest Apple device to date with a thickness of 5.1 millimetres, the company said at the unveiling on Tuesday. Apple used to describe the iPad as its vision for the future of the p…