fix(dev-deps): removes svg-to-ts fixed version and updates to latest

There was a [slight issue](nivekcode/svg-to-ts#91) with a minor version
change in svg-to-ts. We temporarily pinned the version, but the issue has now been resolved.

fix #88

Author: andy-polhill

package-lock.json

@@ -114,7 +114,7 @@
     "stylelint": "^11.1.1",
     "stylelint-config-recommended": "^3.0.0",
     "stylelint-selector-bem-pattern": "^2.1.0",
-    "svg-to-ts": "5.0.1",
+    "svg-to-ts": "^6.0.0",
     "svgo": "^1.3.2",
     "ts-mockito": "^2.6.1",
     "ts-node": "^9.0.0",