Make a start on changelog/upgrade notes for 20

docs/simplesamlphp-changelog.md

@@ -6,6 +6,15 @@ SimpleSAMLphp changelog
 This document lists the changes between versions of SimpleSAMLphp.
 See the upgrade notes for specific information about upgrading.
 
+## Version 2.0.0
+
+  * Support for certificate fingerprints was removed
+  * Support for SAML 1.1 was removed
+  * Old-style PHP templates were removed
+  * Old-style dictionaries were removed
+
+Released TBD
+
 ## Version 1.19.0
 
 Released TBD

docs/simplesamlphp-upgrade-notes-2.0.md

+Upgrade notes for SimpleSAMLphp 2.0
+====================================
+
+- The minimum PHP version required is now PHP 7.2.
+- Old JSON-formatted dictionaries have been replaced by gettext / .po-files;
+    You can find a migration guide here: https://github.com/simplesamlphp/simplesamlphp/wiki/Migrating-translations-(pre-migration)
+- Old PHP templates have been replaced by Twig-templates; you can find a migration
+    guide here: https://github.com/simplesamlphp/simplesamlphp/wiki/Twig:-Migrating-templates
+- The source was completely typehinted; if you have custom authsources or authproc filters, 
+    make sure you change them to reflect the method signatures of the base classes.
+- If you used some of the modules that were shipped with SimpleSAMLphp, you now have to manually install them using Composer;
+    For example, to use the ldap-module: bin/composer.phar require simplesamlphp/simplesamlphp-module-ldap --update-no-dev