feat(semantic-release): implement for this formula

* Based on `ssf-formula` (v0.3.0)
  - https://github.com/myii/ssf-formula/pull/5
* Unable to use `pillar.example` directly for testing
  - Used it as a basis for `test/salt/pillar/default.sls`
  - Brought useful changes back to `pillar.example`
* Fix: avoid `users/googleauth.sls` for `RedHat` & `Suse`
* Close #203

test/integration/default/inspec.yml

@@ -0,0 +1,14 @@
+name: default
+title: users formula
+maintainer: SaltStack Formulas
+license: Apache-2.0
+summary: Verify that the users formula is setup and configured correctly
+supports:
+  - platform-name: debian
+  - platform-name: ubuntu
+  - platform-name: centos
+  - platform-name: fedora
+  - platform-name: opensuse
+  - platform-name: suse
+  - platform-name: freebsd
+  - platform-name: amazon