Change "client" to "SDK"

As we mostly refer to our "SDKs" rather than our "clients",
we've updated our docs to prefer "SDK". This PR makes equivalent
updates to the Go SDK README.

Addresses: https://app.asana.com/0/1206419570114940/1207978475519546/f

README.md

@@ -1,6 +1,6 @@
-# Pinecone Go Client · ![License](https://img.shields.io/github/license/pinecone-io/go-pinecone?color=orange) [![Go Reference](https://pkg.go.dev/badge/github.com/pinecone-io/go-pinecone.svg)](https://pkg.go.dev/github.com/pinecone-io/go-pinecone@main/pinecone) [![Go Report Card](https://goreportcard.com/badge/github.com/pinecone-io/go-pinecone)](https://goreportcard.com/report/github.com/pinecone-io/go-pinecone)
+# Pinecone Go SDK · ![License](https://img.shields.io/github/license/pinecone-io/go-pinecone?color=orange) [![Go Reference](https://pkg.go.dev/badge/github.com/pinecone-io/go-pinecone.svg)](https://pkg.go.dev/github.com/pinecone-io/go-pinecone@main/pinecone) [![Go Report Card](https://goreportcard.com/badge/github.com/pinecone-io/go-pinecone)](https://goreportcard.com/report/github.com/pinecone-io/go-pinecone)
 
-This is the official Go client for [Pinecone](https://www.pinecone.io).
+This is the official Go SDK for [Pinecone](https://www.pinecone.io).
 
 ## Documentation
 
@@ -19,9 +19,9 @@ go-pinecone contains
 
 See the [Pinecone API Docs](https://docs.pinecone.io/reference/) for more information.
 
-## Upgrading your client
+## Upgrading the SDK
 
-To upgrade your client to the latest version, run:
+To upgrade the SDK to the latest version, run:
 
 ```shell
 go get -u github.com/pinecone-io/go-pinecone/pinecone@latest
@@ -33,7 +33,7 @@ go get -u github.com/pinecone-io/go-pinecone/pinecone@latest
 
 ## Installation
 
-To install the Pinecone Go client, run the following in your terminal:
+To install the Pinecone Go SDK, run the following in your terminal:
 
 ```shell
 go get github.com/pinecone-io/go-pinecone/pinecone