minor #11112 fix removing Dotenv from require-dev (xabbuh)

This PR was merged into the 4.2 branch.

Discussion
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fix removing Dotenv from require-dev

fixes #10548 (comment)

Commits
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b33d8c4 fix removing Dotenv from require-dev

Author: javiereguiluz

deployment.rst

@@ -146,7 +146,6 @@ most natural in your hosting environment.
 
     .. code-block:: terminal
 
-        $ composer remove symfony/dotenv
         $ composer require symfony/dotenv
 
 C) Install/Update your Vendors