Bump version 2.7.1

Bump version 2.7.0

Bump version 2.6.0

Bump version to 2.4.1

Version 2.4.0

- Add ability to build filter graph from the string description in the
  FFmpeg-like way
- Fix issue with CMake modules dependency lookup
- Fix issue #134: wrong nb_filters usage

Bump version to 2.3.2

Bump version to 2.3.1

Bump version to 2.3.0

Bump version to 2.2.1

- Fixed usage as library with compilers setted C++ version to 20 and
  newer

Version 2.2.0

- CMake min version was bumped to 3.19
- Updated CI scripts (can be used as sample for building)
- Updated information for Windows cross-building
- Updated samples code
- Added support for Channel Layout in newe FFmpeg versions
  - Added new API to work with channels layouts
  - Handle new Channel Layout API in the Codec, CodecContext,
    AudioSamples components
- Added support for API_FORMAT_URL: AVFormatContext::url
- Handle `AVCodecContext::frame_num` vs `frame_number`
- Reworked logic with FormatContext and Streams work (see deprecation
  warnings on build)
- Added `__STDC_CONSTANT_MACROS` definition for new compliers and FFmpeg
  versions