[#1986] locked the earmark version

next versions break our html render. Need to migrate our HtmlRender to Ast Render based on EarmarkParser.AstRenderer

https://git.pleroma.social/pleroma/pleroma/-/blob/develop/lib/pleroma/earmark_renderer.ex https://github.com/RobertDober/earmark_parser/blob/master/lib/earmark_parser/ast_renderer.ex