removed composer self-update to try to fix 'https://github.com/composer/composer/issues/4121'
removed composer self-update to try to fix 'https://github.com/composer/composer/issues/4121'

RJacksonm1/Embed,JanPetterMG/Embed,younes0/Embed,mburtscher/Embed,davereid/Embed,thenextweb/Embed,zyuhel/Embed,oscarotero/Embed,daveross/Embed