Enable/Disable sso based on env type

[bernattorras]

Changes proposed in this Pull Request

• Enable or disable SSO depending on the environment type:
  • Disables SSO (if it's enabled already) on non-production sites
  • Enables SSO on production sites (if it's not enabled already)
• Bump plugin version to 1.0.3

Testing instructions

• Install and activate this version of the plugin on a production site and confirm that SSO is required in the login page
• Install and activate this version of the plugin on a non-production site and confirm that SSO isn't required anymore

Mentions #1

[wpspecialprojects]

Unable to PHPCS or SVG scan one or more files due to error running PHPCS/SVG scanner:

• includes/class-force-sso.php
• to51-jetpack-force-sso.php

The error may be temporary. If the error persists, please contact a human (commit-ID: 3bbc4fd).

[bernattorras]

I'm merging this fix into trunk because the previous fix wasn't deactivating SSO if it was already active in a non-production site.

[bernattorras]

@tommusrhodus