feat(changelog.md) added chnagelog.md

Signed-off-by: Benoit Mortier <benoit.mortier@fusiondirectory.org>

Changelog.md

+## %"Schema2ldif 1.3" - 2017-04-20
+
+### Added
+
+#### schema2ldif
+- schema2ldif#5478 We should have a generic tool ldap-schema-manager
+
+### Changed
+
+#### schema2ldif
+- schema2ldif#5483 :books: docs: add latest version of contributing.md
+
+## %"Schema2ldif 1.2" - 2016-05-04
+
+### Changed
+
+#### schema2ldif
+- schema2ldif#4573 refresh the manpage that have a wrong version number
+- schema2ldif#4574 refresh copyright date on schema2ldif
+
+### Fixed
+
+#### schema2ldif
+- schema2ldif#4572 update and correct BSD license
+
+## %"Schema2ldif 1.1" - 2014-07-04
+
+### Added
+
+#### schema2ldif
+- schema2ldif#2831 create a changelog for schema2ldif
+
+## %"Schema2ldif 1.0" - 2013-05-06
+
+### Added
+
+#### schema2ldif
+- schema2ldif#2283 A license should be chosen for the tool
+
+### Fixed
+
+#### schema2ldif
+- schema2ldif#2282 Cn inside schema conversion should not have .schema behind schema name
+- schema2ldif#2337 nova_openldap schema failed insertion
+- schema2ldif#2368 Doesn't work for schac.schema
+