Upgraded cython to 3.0.x (#1221)

setup.py

diff --git a/setup.py b/setup.py
index 0e48c3c..79fda90 100644
--- a/setup.py
+++ b/setup.py
@@ -375,7 +375,7 @@
         # 1.) build_ext eats errors at compile time, letting the install complete while producing useful feedback
         # 2.) there could be a case where the python environment has cython installed but the system doesn't have build tools
         if pre_build_check():
-            cython_dep = 'Cython>=0.20,!=0.25,<0.30'
+            cython_dep = 'Cython>=3.0'
             user_specified_cython_version = os.environ.get('CASS_DRIVER_ALLOWED_CYTHON_VERSION')
             if user_specified_cython_version is not None:
                 cython_dep = 'Cython==%s' % (user_specified_cython_version,)

test-requirements.txt

diff --git a/test-requirements.txt b/test-requirements.txt
index 94ac611..6499e20 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -8,7 +8,7 @@
 twisted[tls]
 gevent
 eventlet
-cython>=0.20,<0.30
+cython>=3.0
 packaging
 futurist
 asynctest

tox.ini

diff --git a/tox.ini b/tox.ini
index a8dda2d..6748a6e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,7 +4,7 @@
 [base]
 deps = pytest
        packaging
-       cython>=0.20,<0.30
+       cython>=3.0
        eventlet
        gevent
        twisted[tls]