…#685)

* Target .NET Standard 2.0, .NET Standard 2.1 and .NET 6.0

* Remove master branch restriction from PR workflow

* Add develop branch to CI workflow triggers

* Update workflow to remove master branch restriction

Removed branch specification for pull request trigger.

* Update VersionPrefix to 2.0.0-preview

* Don't test .NET Core 2.1

* Remove .NET Core 2.1 and .NET 5.0 from CI workflows

* Add QRCoder library classes and methods for QR code generation and payload handling

- Implemented abstract class AbstractQRCode and derived classes: ArtQRCode, AsciiQRCode, Base64QRCode, BitmapByteQRCode, PdfByteQRCode, PngByteQRCode, PostscriptQRCode, SvgQRCode, and QRCode.
- Added helper classes for each QR code type to facilitate QR code generation.
- Introduced PayloadGenerator with various payload types including BezahlCode, BitcoinAddress, CalendarEvent, ContactData, Geolocation, Girocode, and more.
- Defined enums for various configurations and options within the QR code generation process.
- Included exception handling classes for managing errors related to data size and specific payload types.
- Established a comprehensive structure for QR code data management with QRCodeData and QRCodeGenerator classes.

* Update

* Fix usings

* update

* update

* Update cross-platform support information in README.md

* Add migration guide for QRCoder v2 and update README.md

* Use ReadOnlySpan

* Target .NET Standard 2.0, .NET Standard 2.1 and .NET 6.0

* Remove master branch restriction from PR workflow

* Add develop branch to CI workflow triggers

* Update workflow to remove master branch restriction

Removed branch specification for pull request trigger.

* Update VersionPrefix to 2.0.0-preview

* Don't test .NET Core 2.1

* Remove .NET Core 2.1 and .NET 5.0 from CI workflows

* Add QRCoder library classes and methods for QR code generation and payload handling

- Implemented abstract class AbstractQRCode and derived classes: ArtQRCode, AsciiQRCode, Base64QRCode, BitmapByteQRCode, PdfByteQRCode, PngByteQRCode, PostscriptQRCode, SvgQRCode, and QRCode.
- Added helper classes for each QR code type to facilitate QR code generation.
- Introduced PayloadGenerator with various payload types including BezahlCode, BitcoinAddress, CalendarEvent, ContactData, Geolocation, Girocode, and more.
- Defined enums for various configurations and options within the QR code generation process.
- Included exception handling classes for managing errors related to data size and specific payload types.
- Established a comprehensive structure for QR code data management with QRCodeData and QRCodeGenerator classes.

* Update

* Fix usings

* update

* update

* Split project to QRCoder.SystemDrawing

* update

* Add additional color names with alternative spellings to ColorTranslator

* Add documentation for known HTML color names in ColorTranslator

* Refactor GetGraphic method to simplify color handling logic

* Refactor GetGraphic method overloads to improve color handling and maintain consistency

* Refactor GetGraphic method to enhance functionality and remove redundancy

* Refactor GetGraphic method to improve clarity and maintain consistency in overloads

* Refactor GetGraphic method to restore and enhance overload with color parameters for improved flexibility

* Refactor GetGraphic method to add overload for enhanced color customization and maintain consistency

* Update

* Update cross-platform support information in README.md

* Add migration guide for QRCoder v2 with new features and breaking changes

* Add migration guide for QRCoder v2 and update README.md

* Update project references and enhance migration documentation for QRCoder v2

* fix usings

* update

* Update QRCoder/Base64QRCode.cs

Co-authored-by: Günther Foidl <gue@korporal.at>

* Use ReadOnlySpan

* Add newlines

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Co-authored-by: Günther Foidl <gue@korporal.at>