minor #10731 Always use latest Symfony version (gbirke)

This PR was merged into the 4.2 branch.

Discussion
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Always use latest Symfony version

Removed the version number of the require command to avoid installing outdated requirements

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Commits
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2804543 Always use latest Symfony version

Author: javiereguiluz

setup/flex.rst

@@ -111,7 +111,7 @@ Symfony application by executing the following command:
 
 .. code-block:: terminal
 
-    $ composer create-project symfony/skeleton:4.1.* my-project
+    $ composer create-project symfony/skeleton my-project
 
 .. note::