comes with (better) compat with iOS 15

- Update to version 1.3.0+git.20210921:
* configure: Revert accidentally committed change with git-version-gen
* [github-actions] Add an explicit apt-get update before attempting to install packages on ubuntu
* [github-actions] macOS: build for arm64 too
* Check availability of constructor attribute and use it on Windows in favor of DllMain
* pkgconfig: Fix libimobiledevice-glue dependency in .pc file
* Add build status badge to README.md
* [github-actions] Build with --enable-debug for all platforms
* [github-actions] Add build workflow
* tools: Fix 'DSO missing from command line' when linking idevicepair on Linux
* Updated pkg-config file with libimobiledevice-glue dependency
* Remove common code in favor of new libimobiledevice-glue
* tools/idevicebackup2: Move some declarations to the start of main function
* tools: idevicebackup2: Exit on service startup failure and improve error messages
* idevice: Reset receive length variable in internal_ssl_read retry loop and fix wrong variable in debug message
* lockdown: Replace udid and mux_id members from client struct with idevice_t reference
* lockdown: Get DeviceClass to make sure OS version dependent code is executed correctly
* Handle error cases in relevant code when retrieving pair record fails
* common: Return proper error codes from userpref_read_pair_record
* Update deprecated autoconf macros and update m4 files
* afc: Suppress compiler warning when compiling without --enable-debug
* Add support for MbedTLS
* idevice: Remove unnecessary memcpy from internal_ssl_read()
* idevice: Route OpenSSL reads/writes through internal_connection_*
* idevice: Make sure to handle timeout condition for network connections too
* README: Fix typo
* installation_proxy: Ignore non-status messages instead of terminating loop
* mobilesync: Set DeviceLink version to 400 to support iOS 14b4+
* tools/idevicecrashreport: Fix illegal filenames on Windows
* common: Add missing *_LIBS and *_CFLAGS to fix build
* tools: Fix usage of LDFLAGS and LDADD.
* tools: Fix entering recovery mode on iOS 14.5+ which now requires a pairing
* Remove redundent `select` call from idevicedebugserverproxy.c
* tools: Flip order of winsock2.h and windows.h in idevicedebugserverproxy to get rid of compiler warning
* tools: Fix delays in idevicedebugserverproxy when using SSL
* tools: Fix idevicedebugserverproxy compilation on Windows
* tools: Improve idevicedebugserverproxy with select() and less threads
* debugserver: Return success when a receive timed out but actualy bytes have been read
* idevice: Allow partial reads in idevice_connection_receive_timeout() and handle timeouts more adequate
* configure: Make sure to also search for cython3 if cython is not found
* Fixed method visibility in mobilebackup2.pxi API
* Fixed bytes/strings checks in lockdown.pxi for compatibility with Python2/3
* Fixed bytes/strings check in imobiledevice.pyx for compatibility with Python2/3
* Fixed debugserver.pxi PyString_AsString compatibility with Python3
* Fixed AFC afc.pxi definitions for Python2/3 compatibility. Added missing public method 'remove_path_and_contents'
* common: Merge socket changes from libusbmuxd
* idevicescreenshot: Remove unnecessary math functions to find a unique filename
* ideviceprovision: Fix date output by adding MAC_EPOCH
* cython: Fix typo in mobilesync.pxi
* docs: Improve --quiet command line switch description in idevicesyslog man page
* include: Fix typo in installation_proxy.h
* README: Fix typo
* idevicescreenshot: Choose a better filename, prevent overwriting existing files
* idevicedebug: Add --detach option to start an app and exit idevicedebug without killing the app
* idevicebackup2: Handle DLMessagePurgeDiskSpace by sending back error code
* idevicebackup2: Update errno to device error mapping
* idevice: Handle -EAGAIN in case usbmuxd_send() returns it
* idevicebackup2: Don't fail on restore when source backup doesn't have any application info