Bump bower from 1.2.8 to 1.8.8

Bumps [bower](https://github.com/bower/bower) from 1.2.8 to 1.8.8.
- [Release notes](https://github.com/bower/bower/releases)
- [Changelog](https://github.com/bower/bower/blob/master/CHANGELOG.md)
- [Commits](https://github.com/bower/bower/compare/v1.2.8...v1.8.8)

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

package.json

@@ -4,7 +4,7 @@
   "description": "A browser firendly .ics/.vcs file generator written entirely in javascript",
   "main": "ics.js",
   "dependencies": {
-    "bower": "~1.2.8",
+    "bower": "~1.8.8",
     "file-saver": "^1.3.3",
     "grunt": "~0.4.2",
     "grunt-contrib-concat": "~0.3.0",