(maint) Update CHANGELOG.md

Mention that release notes are no longer tracked in the CHANGELOG file and link
to the official Puppet documentation.

Author: GabrielNagy

CHANGELOG.md

@@ -1,3 +1,7 @@
+## Facter release notes are now provided as part of the [official Puppet documentation](https://puppet.com/docs/puppet/7/release_notes_facter.html) and are no longer tracked in this file.
+
+# Previous versions
+
 ## [4.0.44](https://github.com/puppetlabs/facter/tree/4.0.44) (2020-10-21)
 
 [Full Changelog](https://github.com/puppetlabs/facter/compare/4.0.43...4.0.44)
@@ -500,4 +504,4 @@
 
 
 
-\* *This Changelog was automatically generated by [github_changelog_generator](https://github.com/github-changelog-generator/github-changelog-generator)*
+\* *This Changelog was automatically generated by [github_changelog_generator](https://github.com/github-changelog-generator/github-changelog-generator)*