Convert unity texture without extension as png

ExtensionlessTexture2DToPNG.cs

[ContextMenuItem("Yo", "Yo")]
    public Texture2D tex;
    public void Yo()
    {
        Texture2D DeCompress(Texture2D source)
        {
            RenderTexture renderTex = RenderTexture.GetTemporary(
                        source.width,
                        source.height,
                        0,
                        RenderTextureFormat.Default,
                        RenderTextureReadWrite.Linear);

            Graphics.Blit(source, renderTex);
            RenderTexture previous = RenderTexture.active;
            RenderTexture.active = renderTex;
            Texture2D readableText = new Texture2D(source.width, source.height);
            readableText.ReadPixels(new Rect(0, 0, renderTex.width, renderTex.height), 0, 0);
            readableText.Apply();
            RenderTexture.active = previous;
            RenderTexture.ReleaseTemporary(renderTex);
            return readableText;
        }
        System.IO.File.WriteAllBytes("C:/UnityProjects/arc/Assets/Models/Primitives/shadow4.png", DeCompress(tex).EncodeToPNG());
    }