Apim changelogs

[Okhelifi]

Description

Some changelogs are missing for APIM old versions. I made a fist PR few weeks ago to add the 4.4.0 and 4.5.0 changelogs. This PR add the changelogs for 4.2.0 and 4.3.0 See :

• https://gravitee.atlassian.net/issues/?jql=fixVersion%20%3D%2010183%20AND%20type%20%3D%20%22Public%20Bug%22%20AND%20project%20%3D%20APIM%20ORDER%20BY%20component%20DESC%2C%20created%20ASC
• https://gravitee.atlassian.net/issues/?jql=type%20%3D%20%22Public%20Bug%22%20AND%20project%20%3D%20APIM%20AND%20fixversion%20%3D%204.3.0%20ORDER%20BY%20component%20ASC%2C%20created%20ASC