Add composer 1.9.1, remove composer 1.9.0
Add composer 1.9.1, remove composer 1.9.0

for stack(s) cflinuxfs3 [#169507186]

cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack,cloudfoundry/php-buildpack