Bump bower from 1.7.7 to 1.8.8

Bumps [bower](https://github.com/bower/bower) from 1.7.7 to 1.8.8.
- [Release notes](https://github.com/bower/bower/releases)
- [Changelog](https://github.com/bower/bower/blob/master/CHANGELOG.md)
- [Commits](bower/bower@v1.7.7...v1.8.8)

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -28,7 +28,7 @@
     "grunt-version": "~0.2.2",
     "load-grunt-tasks": "^3.3.0",
     "phantomjs": "1.9.8",
-    "bower": "1.7.7",
+    "bower": "1.8.8",
     "casperjs": "1.1.0"
   }
 }