update readme and bump plugin version to 3.4

bump version to 3.3

rename opacity to transparency on layers editor screen

fix auto-generation bug and preset fields race-condition in Gutenberg…

… sidebar

fix sidebar problem in FSE editor

fix missing translation handler in settings editor

add optional context parameter to sharing_image_prepare_template filt…

…er and gif poster format

update github action

fix poster background opacity on template editor screen

added second parameter to public template functions