docs: fix go get -tool command (#5669)

Author: kasaikou

docs/src/docs/welcome/install.mdx

@@ -203,7 +203,7 @@ go tool -modfile=golangci-lint.mod golangci-lint run
 
 ```sh
 # Update golangci-lint
-go get -tool -modfile=golangci-lint.mod github.com/golangci/v2/golangci-lint/cmd/golangci-lint@latest
+go get -tool -modfile=golangci-lint.mod github.com/golangci/golangci-lint/v2/cmd/golangci-lint@latest
 ```
 
 **Method 2: dedicated module**