build(deploy): add semantic-release

Add semantic-release and configure it to run in a deploy stage on
TravisCI.

Author: Arcanemagus

.github_changelog_generator

@@ -2,8 +2,8 @@
 __tests__/*
 .circleci/*
 coverage/*
+.gitattributes
+.gitignore
 .npmignore
 .travis.yml
-.gitignore
-.gitattributes
-.github_changelog_generator
+git_deploy_key.enc

.npmignore

@@ -24,7 +24,7 @@ jobs:
         provider: script
         skip_cleanup: true
         script:
-          - echo "npx semantic-release"
+          - npx semantic-release
 
 notifications:
   email: