Avoid random grpcio log messages from grpcio >= 1.65 (#290)

## Problem

Avoid the random log messages printed by newer versions of grpcio:

```
WARNING: All log messages before absl::InitializeLog() is called are written to STDERR
E0000 00:00:1736518320.409980 62387854 init.cc:229] grpc_wait_for_shutdown_with_timeout() timed out.
```

Upstream GH issue: grpc/grpc#37222

This mentions it is fixed in protobuf v27.3; however that's numbered in
python land as 5.27 and hence is a new major version which the
'pinecone' Python package is not compatible with:

```
❯ poetry show protobuf
 name         : protobuf
 version      : 4.25.5
 description  :

required by
 - google-api-core >=3.19.5,<3.20.0 || >3.20.0,<3.20.1 || >3.20.1,<4.21.0 || >4.21.0,<4.21.1 || >4.21.1,<4.21.2 || >4.21.2,<4.21.3 || >4.21.3,<4.21.4 || >4.21.4,<4.21.5 || >4.21.5,<6.0.0.dev0
 - googleapis-common-protos >=3.20.2,<4.21.1 || >4.21.1,<4.21.2 || >4.21.2,<4.21.3 || >4.21.3,<4.21.4 || >4.21.4,<4.21.5 || >4.21.5,<6.0.0.dev0
 - pinecone >=4.25,<5.0
 - proto-plus >=3.19.0,<6.0.0dev
 - protoc-gen-openapiv2 >=4.21.0
```

## Solution

Downgrade to grpcio 1.64. We will have to wait until pinecone supports
5.27 before allowing a newer version of grpcio / protobuf.

## Type of Change

- [x] Bug fix (non-breaking change which fixes an issue)

pyproject.toml

@@ -10,7 +10,7 @@ python = "^3.11"
 locust = "^2.32.5"
 pandas = "^2.2.3"
 google-cloud-storage = "^2.18.2"
-grpcio = "^1.66.1"
+grpcio = "1.64.1"
 pyarrow = "^18.0.0"
 pinecone = {version = "^5.0", extras = ["grpc"]}
 tabulate = "^0.9.0"