try fix bitarray on pypy

setup.py

@@ -32,6 +32,7 @@
 from setuptools.command.test import test as test_command
 
 CPY = platform.python_implementation() == 'CPython'
+PYPY = platform.python_implementation() == 'PyPy'
 
 # read version string
 with open('autobahn/_version.py') as f:
@@ -112,9 +113,22 @@
 if 'AUTOBAHN_USE_NVX' not in os.environ or os.environ['AUTOBAHN_USE_NVX'] not in ['0', 'false']:
     cffi_modules.append('autobahn/nvx/_utf8validator.py:ffi')
 
+if PYPY:
+    # bitarray is required by eth-account, but on pypy:
+    #
+    # https://github.com/crossbario/autobahn-python/pull/1617#issuecomment-1492005329
+    # https://github.com/ilanschnell/bitarray/issues/188
+    #
+    # us bitarray upstream master until next upstream release
+    # {package-name}[flavor] @ git+https://github.com/{user|org}/{repository}.git@{tag}#egg={package-name}
+    # https://peps.python.org/pep-0508/
+    extras_require_xbr = ["bitarray @ git+https://github.com/ilanschnell/bitarray.git@master#bitarray"]
+else:
+    extras_require_xbr = ["bitarray>=2.7.3"]
+
 # https://peps.python.org/pep-0440/#direct-references
 # https://stackoverflow.com/a/63688209/884770
-extras_require_xbr = [
+extras_require_xbr.extend([
     # XBR contracts and ABI file bundle
     'xbr>=21.2.1',              # Apache 2.0
 
@@ -151,7 +165,7 @@
     # the following is needed for XBR account synch and device pairing
     'spake2>=0.8',              # MIT license (https://github.com/warner/python-spake2/blob/master/LICENSE)
     'hkdf>=0.0.3',              # BSD 2-Clause "Simplified" License
-]
+])
 
 # required for UI based tools, e.g. xbrnetwork-ui (autobahn.xbr._gui:_main)
 extras_require_ui = [