ZXing: no need for deprecated utf-8 conversions anymore

With ZXing 2.0, the library directly supports utf8 std::string
parameters: https://github.com/zxing-cpp/zxing-cpp/releases/tag/v2.0.0

Fixes the warning:

 cui/source/dialogs/QrCodeGenDialog.cxx:161:72: warning: 'FromUtf8' is deprecated [-Wdeprecated-declarations]
  161 |     ZXing::BitMatrix bitmatrix = writer.encode(ZXing::TextUtfEncoding::FromUtf8(QRText), 0, 0);
      |                                                                        ^
 /usr/include/ZXing/TextUtfEncoding.h:17:3: note: 'FromUtf8' has been explicitly marked deprecated here
   17 | [[deprecated]] std::wstring FromUtf8(std::string_view utf8);
      |   ^

Change-Id: Ic0a65d4455dabea1a7a4e23f558e4158a0c3f39f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/161182
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <thorsten.behrens@allotropia.de>

cui/source/dialogs/QrCodeGenDialog.cxx

@@ -19,6 +19,7 @@
 #include <vcl/svapp.hxx>
 
 #if ENABLE_ZXING
+#include <ZXVersion.h>
 #include <rtl/strbuf.hxx>
 
 #ifdef __GNUC__
@@ -38,9 +39,7 @@
 #include <BitMatrixIO.h>
 #endif
 
-#if __has_include(<Utf.h>)
-#include <Utf.h>
-#else
+#if ZXING_VERSION_MAJOR < 2
 #include <TextUtfEncoding.h>
 #endif
 
@@ -153,8 +152,8 @@ OString GenerateQRCode(std::u16string_view aQRText, tools::Long aQRECC, int aQRB
     ZXing::BarcodeFormat format = ZXing::BarcodeFormatFromString(GetBarCodeType(aQRType));
     auto writer = ZXing::MultiFormatWriter(format).setMargin(aQRBorder).setEccLevel(bqrEcc);
     writer.setEncoding(ZXing::CharacterSet::UTF8);
-#if __has_include(<Utf.h>)
-    ZXing::BitMatrix bitmatrix = writer.encode(ZXing::FromUtf8(QRText), 0, 0);
+#if ZXING_VERSION_MAJOR >= 2
+    ZXing::BitMatrix bitmatrix = writer.encode(QRText, 0, 0);
 #else
     ZXing::BitMatrix bitmatrix = writer.encode(ZXing::TextUtfEncoding::FromUtf8(QRText), 0, 0);
 #endif