Set grpcio minimum version to 1.59.3 so that Alpine py3-grpcio 1.59.3 can be used (#211)

- there's no specific minimum version constraint originating from pulsar-client-python
  - grpcio is required by apache-bookkeeper-client. the dependencies are defined in
    https://github.com/apache/bookkeeper/blob/master/stream/clients/python/setup.py
    the version in this file is >= 1.8.2
diff --git a/setup.py b/setup.py
index 8055af0..bef1107 100755
--- a/setup.py
+++ b/setup.py
@@ -80,7 +80,7 @@
 extras_require["functions"] = sorted(
     {
       "protobuf>=3.6.1,<=3.20.3",
-      "grpcio>=1.60.0",
+      "grpcio>=1.59.3",
       "apache-bookkeeper-client>=4.16.1",
       "prometheus_client",
       "ratelimit"