Bump semver from 5.4.1 to 6.1.0 in /terminus-plugin-manager

Bumps [semver](https://github.com/npm/node-semver) from 5.4.1 to 6.1.0.
- [Release notes](https://github.com/npm/node-semver/releases)
- [Changelog](https://github.com/npm/node-semver/blob/master/CHANGELOG.md)
- [Commits](https://github.com/npm/node-semver/compare/v5.4.1...v6.1.0)

terminus-plugin-manager/package.json

@@ -23,7 +23,7 @@
     "@types/webpack-env": "1.13.0",
     "css-loader": "^0.28.0",
     "ngx-pipes": "^1.6.1",
-    "semver": "^5.3.0"
+    "semver": "^6.1.0"
   },
   "peerDependencies": {
     "@angular/common": "4.0.1",

terminus-plugin-manager/yarn.lock

@@ -3120,10 +3120,10 @@ semver-diff@^2.0.0:
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.6.0.tgz#7e74256fbaa49c75aa7c7a205cc22799cac80004"
   integrity sha512-RS9R6R35NYgQn++fkDWaOmqGoj4Ek9gGs+DPxNUZKuwE183xjJroKvyo1IzVFeXvUrvmALy6FWD5xrdJT25gMg==
 
-semver@^5.3.0:
-  version "5.4.1"
-  resolved "https://registry.yarnpkg.com/semver/-/semver-5.4.1.tgz#e059c09d8571f0540823733433505d3a2f00b18e"
-  integrity sha512-WfG/X9+oATh81XtllIo/I8gOiY9EXRdv1cQdyykeXK17YcUW3EXUAi2To4pcH6nZtJPr7ZOpM5OMyWJZm+8Rsg==
+semver@^6.1.0:
+  version "6.1.0"
+  resolved "https://registry.yarnpkg.com/semver/-/semver-6.1.0.tgz#e95dc415d45ecf03f2f9f83b264a6b11f49c0cca"
+  integrity sha512-kCqEOOHoBcFs/2Ccuk4Xarm/KiWRSLEX9CAZF8xkJ6ZPlIoTZ8V5f7J16vYLJqDbR7KrxTJpR2lqjIEm2Qx9cQ==
 
 semver@~5.3.0:
   version "5.3.0"