chore(package): update @semantic-release/exec to version 5.0.0

Closes #42

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "@ember/optional-features": "^0.7.0",
     "@semantic-release/changelog": "^3.0.2",
     "@semantic-release/commit-analyzer": "^6.1.0",
-    "@semantic-release/exec": "^3.3.2",
+    "@semantic-release/exec": "^5.0.0",
     "@semantic-release/git": "^7.0.8",
     "@semantic-release/github": "^5.2.10",
     "@semantic-release/release-notes-generator": "^7.1.4",