fix: close resp body (#3364)

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Signed-off-by: guoguangwu <guoguangwug@gmail.com>

clientapi/threepid/threepid.go

@@ -83,6 +83,7 @@ func CreateSession(
 	if err != nil {
 		return "", err
 	}
+	defer resp.Body.Close()
 
 	// Error if the status isn't OK
 	if resp.StatusCode != http.StatusOK {