Fix unicode in bootcamp name

This should fix #503 since instead of

~~~
$ git rev-parse HEAD
d9b1d44a6ed0747b3a7dd2589bb3dbff595fd5bf
$ make clean site
...
$ grep Centro _config.yml 
  venue: "Centro de Compet\xEAncia em Software Livre"
  venue: "Centro de Compet\xEAncia em Software Livre"
~~~

with this PR we have

~~~
$ git rev-parse HEAD       
485b100f504c4f40e80cff2fefb3f3ccd8b29b67
$ make clean site
...
$ grep Centro _config.yml
  venue: Centro de Competência em Software Livre
  venue: Centro de Competência em Software Livre
~~~

@gvwilson Could you review this?