Fixing build issues on MacOS Sequoia

[waschinski]

I tried installing this tool via brew on Sequoia but building it failed due to this:

/tmp/pdfbooklet-20241213-29081-7bnbx1/pdfbooklet-1.0/pdfbooklet.xcodeproj: warning: The macOS deployment target 'MACOSX_DEPLOYMENT_TARGET' is set to 10.9, but the range of supported deployment target versions is 10.13 to 15.1.99. (in target 'pdfbooklet' from project 'pdfbooklet') ** BUILD FAILED **

So I ended up opening the project in Xcode, changing MACOSX_DEPLOYMENT_TARGET to 10.13 and it was building successfully again using xcodebuild.