Fix http section documentation (#32)

* Update invalid link to the example

* Wrong first type of parameter given to NewHTTPRequest function

Author: Zwiterrion

README.md

@@ -215,13 +215,13 @@ extism call plugin.wasm log_stuff --wasi --log-level=trace
 
 ## HTTP
 
-Sometimes it is useful to let a plug-in [make HTTP calls](https://pkg.go.dev/github.com/extism/go-pdk#HTTPRequest.Send). [See this example](example/http.go)
+Sometimes it is useful to let a plug-in [make HTTP calls](https://pkg.go.dev/github.com/extism/go-pdk#HTTPRequest.Send). [See this example](example/http/tiny_main.go)
 
 ```go
 //export http_get
 func httpGet() int32 {
 	// create an HTTP Request (withuot relying on WASI), set headers as needed
-	req := pdk.NewHTTPRequest("GET", "https://jsonplaceholder.typicode.com/todos/1")
+	req := pdk.NewHTTPRequest(pdk.MethodGet, "https://jsonplaceholder.typicode.com/todos/1")
 	req.SetHeader("some-name", "some-value")
 	req.SetHeader("another", "again")
 	// send the request, get response back (can check status on response via res.Status())