added qrcode

Instructions/QRCode.cs

@@ -0,0 +1,26 @@
+using System.Runtime.Serialization;
+using System.Text.Json.Serialization;
+using ESCPOS_NET.Emitters;
+
+public class QRCode : BaseInstruction
+{
+    [DataMember(IsRequired = true)]
+    public string? data { get; set; }
+
+    [JsonConverter(typeof(JsonStringEnumConverter))]
+    public TwoDimensionCodeType barcodeType {get; set; } = TwoDimensionCodeType.QRCODE_MODEL2;
+
+    [JsonConverter(typeof(JsonStringEnumConverter))]
+    public Size2DCode size {get; set; } = Size2DCode.NORMAL;
+
+    [JsonConverter(typeof(JsonStringEnumConverter))]
+    public CorrectionLevel2DCode correctionLevel {get; set; } = CorrectionLevel2DCode.PERCENT_7;
+    public override List<byte[]> GetInstructions()
+    {
+        var commands = new List<byte[]>();
+
+        commands.Add(e.PrintQRCode(data,barcodeType,size,correctionLevel));
+
+        return commands;
+    }
+}