Add update process to the changelog.

CHANGELOG.md

@@ -12,5 +12,18 @@
 * The self-signed certificate generation now uses a configuration template, which includes a `subjectAltName` ([issue #50](https://github.com/palantirnet/the-vagrant/issues/50), [PR #51](https://github.com/palantirnet/the-vagrant/pull/51)
 * The templated Vagrantfile now requires Vagrant >= 2.1.0 ([issue #52](https://github.com/palantirnet/the-vagrant/issues/52), [PR #54](https://github.com/palantirnet/the-vagrant/pull/54))
 
+### Updating from 2.1.0
+
+* This update does **not** require destroying your current vagrant box.
+* These steps apply for projects that have not copied the full set of provisioning into their project; if there is a `provisioning/` directory in your project root, you may not receive the full set of fixes with these steps alone.
+
+1. Uninstall the vagrant-triggers plugin with `vagrant plugin uninstall vagrant-triggers`
+1. Update to Vagrant >= 2.1.0
+1. In your project, require this new release of the-vagrant
+1. In your project, run `vendor/bin/the-vagrant-installer`
+1. Respond to the prompts to regenerate your `Vagrantfile`
+1. Review the changes to make sure that you don't lose any customizations you had to this file
+1. Run `vagrant up --provision` or `vagrant reload --provision` to update your box
+
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 Copyright 2018 Palantir.net, Inc.