Revive the changelog

[tiffon]

Which problem is this PR solving?

The changelog is out of date.

Short description of the changes

Bringing the changelog current.

Also, this switches to a format where we formally bless master as release ready by cutting a release in GitHub.

[codecov]

Codecov Report

Merging #300 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #300   +/-   ##
=======================================
  Coverage   82.57%   82.57%           
=======================================
  Files         140      140           
  Lines        3151     3151           
  Branches      651      651           
=======================================
  Hits         2602     2602           
  Misses        438      438           
  Partials      111      111

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[everett980]

What is the distinction between Next and Changes merged into master? Seems like the 4 PRs currently under Next are all also part of master but not listed under Changes merged into master

[tiffon]

@everett980 Historically, we haven't used semantic versioning with the UI because we have had only minimal API contracts. We just merged everything to master and the jaeger repo would pull in the changes as they saw fit. However, now that we've added embedded mode (#263 followed by #286) we've exposed an API by way of the query parameters used to configure the embedded views.

It seems prudent to start using semantic versioning to indicate whether or not changes have any impact on our API contract(s). With this approach, a set of changes merged to master but not yet characterized by a semantic version can be considered unreleased.

The Changes merged into master are already released in Jaeger 1.8.2.

[everett980]

Looks good, once we have done a few releases we'll probably want a (fairly short) document on the release process.