Combine back into single CHANGELOG to simplify searches

[shadowspawn]

Pull Request

Problem

My motivation for splitting up the CHANGELOG in #1115 was largely to reduce the size of the published package. However, the CHANGELOG is no longer included in the package if published using npm 8 or npm 9. Hurrah!

I have found two annoyances with split CHANGELOG

• it is more complicated searching the CHANGELOGs to see what version a change shipped in
• splitting out the CHANGELOG when a version drops out of support is a tedious amount of manual work to move the issue and PR references

Solution

Put them back together again!

[abetomo]

👍