Apple have release iOS 8.4 today ready for the launch of Apple Music. Sadly the update has not gone without a hitch with many users running iOS 8.4 beta reporting their devices are stuck on “update requested”. Thankfully I have the fix:
Go into settings/general/profiles. Remove the iOS beta profile and reboot your device. The update should then work!
EDIT just adding a bit more info from some questions seen on reddit. Yes this will mean you no longer download beta updates but you can simply redownload the profile once updated either right now at apple.com/beta or when iOS 9 public beta is released next month