chore(package): update semver to version 6.3.0 (#109)

Closes #107

Author: maxdavidson

package.json

@@ -56,7 +56,7 @@
     "rollup-plugin-node-resolve": "^3.0.0",
     "rollup-plugin-sourcemaps": "^0.4.1",
     "rollup-plugin-terser": "^3.0.0",
-    "semver": "^5.6.0",
+    "semver": "^6.3.0",
     "ts-jest": "~23.10.0",
     "tslint": "^5.11.0",
     "tslint-config-prettier": "^1.13.0",