chore: use v2 in the code examples

Author: kkweon

Diff for: README.md

@@ -12,7 +12,7 @@ For Python version, see https://github.com/paperswithcode/paperswithcode-client
 ## Quick usage example
 
 ```go
-import "github.com/codingpot/paperswithcode-go"
+import "github.com/codingpot/paperswithcode-go/v2"
 ```
 
 ```go

Diff for: client_example_test.go

@@ -3,7 +3,7 @@ package paperswithcode_go_test
 import (
 	"fmt"
 
-	paperswithcode_go "github.com/codingpot/paperswithcode-go/v2"
+	"github.com/codingpot/paperswithcode-go/v2"
 )
 
 func Example() {