Add entry to CHANGELOG.md for 40.0.0 (#733)

* Add entry to CHANGELOG.md for 40.0.0

Merge pull request #732 from atlassian/prepare-release-39.1.13

Add entry to CHANGELOG.md for 39.1.3

Merge pull request #727 from atlassian/fix-tag-concat

assign new tag value after concat

Merge pull request #721 from atlassian/htan/prepare-39.1.11

update changelog for r39.1.11

Merge pull request #719 from atlassian/htan/retry-test

add tests and refactor retry sending

Merge pull request #716 from atlassian/htan/39.1.9

update changelog for 39.1.9

Merge pull request #714 from atlassian/prepare-39.1.8-release

update changelog for release 39.1.8

Merge pull request #706 from atlassian/waynewu411/release-39.1.7

Release 39.1.7

Merge pull request #703 from atlassian/htan/prep-39.1.6

Prepare release for 39.1.6

Merge pull request #700 from atlassian/waynewu411/release-39.1.5

Changelog for release 39.1.5