updated VENDORS for 3.1.8
updated VENDORS for 3.1.8

debruyne0/symfony,simonjcarr/symfony_rest,lyrixx/symfony-standard,Tobion/symfony-standard,the-software-factory/superhero-api,Tobion/symfony-standard,egeloen/symfony-standard,vincentaubert/symfony-standard,formapro-forks/api-basic,symfony-cmf/standard-edition,stof/symfony-standard,lyrixx/symfony-standard,kmelia/fresh-symfony,uttam-vi/pardawala,kmelia/fresh-symfony,ovelasquez/ussi,uttam-vi/pardawala,gencer/symfony-standard,egeloen/symfony-standard,symfony-cmf/standard-edition,gencer/symfony-standard,ovelasquez/ussi,the-software-factory/superhero-api,simonjcarr/symfony_rest,symfony/symfony-standard,formapro-forks/api-basic,uttam-vi/pardawala,vincentaubert/symfony-standard,kmelia/fresh-symfony,symfony/symfony-standard,ovelasquez/ussi,debruyne0/symfony,stof/symfony-standard