fix(deps): allow pyarrow version 7+ (googleapis#479)

* feat: Support PyArrow versions 3.0.0 through 9 (googleapis#479)

* allow pyarrow < 10

* remove top constraint

Co-authored-by: Anthonios Partheniou <partheniou@google.com>
Co-authored-by: Tim Swast <swast@google.com>

setup.py

@@ -85,7 +85,7 @@ def readme():
         "google-auth>=1.25.0,<3.0.0dev",  # Work around pip wack.
         "google-cloud-bigquery>=2.25.2,<4.0.0dev",
         "google-cloud-bigquery-storage>=2.0.0,<3.0.0dev",
-        "pyarrow>=3.0.0,<7.0dev",
+        "pyarrow>=3.0.0",
         "sqlalchemy>=1.2.0",
         "future",
     ],