Update to 7.0.8.2

Changelog:
2018-06-18  7.0.8-2 Cristy  <quetzlzacatenango@image...>
  * Release ImageMagick version 7.0.8-2, GIT revision 14476:cda11d81d:20180618.

2018-06-18  7.0.8-2 Cristy  <quetzlzacatenango@image...>
  * More robust SVG text handling.

2018-06-16  7.0.8-1 Cristy  <quetzlzacatenango@image...>
  * Release ImageMagick version 7.0.8-1, GIT revision 14468:94cb08785:20180616.

2018-06-16  7.0.8-1 Cristy  <quetzlzacatenango@image...>
  * Fixed numerous use of uninitialized values, integer overflow, memory
    exceeded, and timeouts (credit to OSS Fuzz).
  * Fixed an issue with stroke and label: (reference
    https://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=34142).
  * PNG: set storage class to DirectClass if alpha enabled (reference
    https://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=34121).

(ryoon)