UPDATE 2-Brazil's Lula launches reelection bid, aims to win back workers to his Workers Party

(Adds Senator Flavio Bolsonaro's remarks in paragraphs 29-30) * Lula launches reelection bid where he once led workers' strikes * Gig economy, shrinking unions challenge Lula's Workers Party * Party's

(The article has been published through a syndicated feed. Except for the headline, the content has been published verbatim. Liability lies with original publisher.)