minor symfony#7393 Update sing up link to the Azure cloud platform (florianrusch, javiereguiluz)

This PR was submitted for the 3.2 branch but it was merged into the 2.7 branch instead (closes symfony#7393).

Discussion
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Update sing up link to the Azure cloud platform

The link to the sing up page was broken.

Commits
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6057a13 Use the international signup page instead of the local one
7fd29b6 Update sing up link to the Azure cloud plattform

Author: xabbuh

deployment/azure-website.rst

@@ -452,7 +452,7 @@ and executed on a Microsoft IIS web server. The process is simple and easy
 to implement. And as a bonus, Microsoft is continuing to reduce the number
 of steps needed so that deployment becomes even easier.
 
-.. _`sign up with Azure`: https://signup.live.com/signup.aspx
+.. _`sign up with Azure`: https://azure.microsoft.com/free/
 .. _`Azure Portal`: https://portal.azure.com
 .. _`PHP MSDN documentation`: http://blogs.msdn.com/b/silverlining/archive/2012/07/10/configuring-php-in-windows-azure-websites-with-user-ini-files.aspx
 .. _`git-scm.com`: http://git-scm.com/download