Merge pull request #51 from ConvertAPI/changelog-2.13.1

Changelog for 2.13.1

[maven-release-plugin] copy for tag v2.13

[maven-release-plugin] copy for tag v2.12

[maven-release-plugin] copy for tag v2.11

[maven-release-plugin] copy for tag v2.10

[maven-release-plugin] copy for tag v2.9

[maven-release-plugin] copy for tag v2.8

[maven-release-plugin] copy for tag v2.7

[maven-release-plugin] copy for tag v2.6

[maven-release-plugin] copy for tag v2.5