Added public certificate (PEM) of https://security.sensiolabs.org/
merged branch pborreli/add-certificate (PR #14)

This PR was merged into the master branch.

Commits
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dcafc66 Added public certificate (PEM) of https://security.sensiolabs.org/

Discussion
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Fix curl on windows

On windows this error occurs :

```
An error occurred: SSL certificate problem, verify that the CA cert is OK. Det
ails:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify faile
d.
```
Instead of disabling SSL check I propose to add the certificate (PEM) of https://security.sensiolabs.org/ to the repo and enable it (it is valid until 17/02/2018)