buildtools-installer: Update to use 3.4

This updates buildtools to use the tarball from the 3.4 release which
contains some bug fixes and is what the autobuilder currently uses for
testing on older distros.

(From OE-Core rev: 7479861c60a1c205b9502c1a811ac3a9dc51cd07)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/install-buildtools

@@ -57,9 +57,9 @@ logger = scriptutils.logger_create(PROGNAME, stream=sys.stdout)
 
 DEFAULT_INSTALL_DIR = os.path.join(os.path.split(scripts_path)[0],'buildtools')
 DEFAULT_BASE_URL = 'http://downloads.yoctoproject.org/releases/yocto'
-DEFAULT_RELEASE = 'yocto-3.2_M3'
-DEFAULT_INSTALLER_VERSION = '3.1+snapshot'
-DEFAULT_BUILDDATE = '20200923'
+DEFAULT_RELEASE = 'yocto-3.4'
+DEFAULT_INSTALLER_VERSION = '3.4'
+DEFAULT_BUILDDATE = '202110XX'
 
 # Python version sanity check
 if not (sys.version_info.major == 3 and sys.version_info.minor >= 4):