Build release xcframework deliverable with Xcode 15

[armcknight]

Looks like we still build it with Xcode 14.3:

sentry-cocoa/.github/workflows/build.yml

Lines 87 to 92 in bb5dc7d

	build-xcframework:
	name: Build XCFramework
	runs-on: macos-13
	steps:
	- uses: actions/checkout@v4
	- run: ./scripts/ci-select-xcode.sh

sentry-cocoa/scripts/ci-select-xcode.sh

Line 11 in bb5dc7d

XCODE_VERSION="${1:-14.3}"

Related to #3329