CBS 5 calls it a "boycott," which might be an extreme way of looking at it, but yes, Politico reports that Apple will not lend any help to the GOP convention over the controversial statements of Donald Trump, which is a break from other tech companies and its own history of bipartisan support for such things.
Republican leaders were informed privately of the move by Apple, and the New York Times confirmed the matter, writing judiciously that the company would "withhold its support."
Campaign finance records show that in 2008 Apple provided $140,000 to each major party for MacBooks and more at events like the parties' conventions. In 2012, the company merely lent products to both parties. When asked for a comment about the move, a Republican party spokesperson said that "We are working with a variety of major tech partners who are focused on being part of the American political process," a statement with some implications!
By contrast, Microsoft will provide computers and software for the GOP convention, if not outright funds. Facebook has pledged support, financial and otherwise, for the June convention, and while CEO Mark Zuckerberg, an advocate for immigration reform, has voiced criticism for Trump's stances on the matter, Facebook board member Peter Thiel is an avowed Trump supporter and a pledged delegate for the candidate. Facebook landed in hot water with conservatives earlier this year when the company was accused of suppressing conservative news from its curated "trending topics" section, and Zuck tried to smooth things over in a meeting with Glenn Beck and other conservative thought leaders.
In the past, Trump has sparred with Apple over its perceived non-compliance with the government over an encrypted iPhone used by the San Bernardino mass murderer, of which the Verge writes here.
Related: Peter Thiel, Trump-Loving Tech Billionaire, Maybe Also Suing Gawker Over Article On Trump's 'Hair'