Bump mithril from 1.1.6 to 1.1.7 in /ait/gui/static

Bumps [mithril](https://github.com/MithrilJS/mithril.js) from 1.1.6 to 1.1.7.
- [Release notes](https://github.com/MithrilJS/mithril.js/releases)
- [Commits](MithrilJS/mithril.js@v1.1.6...v1.1.7)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

ait/gui/static/package-lock.json

@@ -26,7 +26,7 @@
     "jsdom": "^9.11.0",
     "jsdom-global": "^2.1.1",
     "lodash": "^4.17.11",
-    "mithril": "^1.1.0",
+    "mithril": "^1.1.7",
     "mithril-query": "2.2.0",
     "mocha": "^3.1.2",
     "sinon": "4.5.0",