minor symfony#7276 Fix spelling error in Travis CI code (dsuurlant)

This PR was submitted for the 3.2 branch but it was merged into the 2.7 branch instead (closes symfony#7276).

Discussion
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Fix spelling error in Travis CI code

Commits
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61547c4 Fix spelling error in Travis CI code

Author: xabbuh

setup/bundles.rst

@@ -151,7 +151,7 @@ following recommended configuration as the starting point of your own configurat
             - php: 5.6
               env: SYMFONY_VERSION='3.1.*'
             - php: 5.6
-              env: DEPENDENCES='dev' SYMFONY_VERSION='3.2.*@dev'
+              env: DEPENDENCIES='dev' SYMFONY_VERSION='3.2.*@dev'
 
     before_install:
         - composer self-update