Return finfo media type in GD mediaTypeByBinary() (#1557)

Add support for decoding images from Psr7 stream/response (#1552)

* Add support for decoding psr7 stream objects
* Add support for decoding psr7 http responses

Fill new GD rotation areas in imagerotate() (#1550)

The background was painted on the new canvas and a transparent cutout
polygon drawn where the rotated image goes, while imagerotate() filled
the new areas with a transparent color. The polygon does not match the
area covered by imagerotate() exactly, so a seam of transparent pixels
was left along the edges of the rotated image on opaque backgrounds.

Let imagerotate() fill the new areas with the background color and copy
the result without blending, which makes the cutout unnecessary.

libgd fills pixels of the transparent color with this color when
rotating, so images with a transparent color (GIF, indexed PNG) are
first copied to a truecolor image without one. The background is no
longer allocated in the frame palette, which returned false on a full
palette and made imagerotate() throw a TypeError.

Fix resolution unit in Imagick ResolutionModifier

Merge branch 'develop'

Add tested support for PHP 8.6 (#1493)

[3.x] Add tested support for PHP 8.6 (#1531)

* Add tested support for PHP 8.6

* Fix AbstractDecoder::isFile()

Merge branch 'develop'

Remove JsonSerializable from EncodedImage (#1522)

* Remove JsonSerializable from EncodedImage

* Tighten regression test comment and imports

Implement JsonSerializable for related classes (#1513)