chore(changelog.md): update 5.12.6 and 5.12.3 (#3715)

5.12.6's changelog accidentally included all the 5.12.x changes and the
link to the comparison was from 5.10.7 to 5.12.6.

The comparison link in 5.12.3 was also updated to properly refer to
5.12.2 as the previous change.

CHANGELOG.md

@@ -1,46 +1,10 @@
 <a name="5.12.6"></a>
-## [5.12.6](https://github.com/videojs/video.js/compare/v5.10.7...v5.12.6) (2016-10-25)
+## [5.12.6](https://github.com/videojs/video.js/compare/v5.12.5...v5.12.6) (2016-10-25)
-
-### Features
-
-* **lang:** add missing translations in fr.json ([280ecd4](https://github.com/videojs/video.js/commit/280ecd4))
-* **lang:** add missing translations to el.json ([eb0efd4](https://github.com/videojs/video.js/commit/eb0efd4))
 
 ### Bug Fixes
 
-* **controls:** fix load progress bar never highlighting first buffered time range ([ca02298](https://github.com/videojs/video.js/commit/ca02298))
-* **css:** remove commented out css ([5fdcd46](https://github.com/videojs/video.js/commit/5fdcd46)), closes [#3587](https://github.com/videojs/video.js/issues/3587)
-* disable HLS hack on Firefox for Android ([#3586](https://github.com/videojs/video.js/issues/3586)) ([dd2aff0](https://github.com/videojs/video.js/commit/dd2aff0))
-* **html5:** disable manual timeupdate events on html5 tech ([#3656](https://github.com/videojs/video.js/issues/3656)) ([920c54a](https://github.com/videojs/video.js/commit/920c54a))
-* logging failing on browsers that don't always have console ([#3686](https://github.com/videojs/video.js/issues/3686)) ([e932061](https://github.com/videojs/video.js/commit/e932061))
 * make sure that document.createElement exists before using ([#3706](https://github.com/videojs/video.js/issues/3706)) ([49e29ba](https://github.com/videojs/video.js/commit/49e29ba)), closes [#3665](https://github.com/videojs/video.js/issues/3665)
-* move html5 source handler incantation to bottom ([#3695](https://github.com/videojs/video.js/issues/3695)) ([7b9574b](https://github.com/videojs/video.js/commit/7b9574b))
-* proxy ios webkit events into fullscreenchange ([#3644](https://github.com/videojs/video.js/issues/3644)) ([e479f8c](https://github.com/videojs/video.js/commit/e479f8c))
 * remove unnecessary comments from video.min.js ([#3709](https://github.com/videojs/video.js/issues/3709)) ([fe760a4](https://github.com/videojs/video.js/commit/fe760a4)), closes [#3707](https://github.com/videojs/video.js/issues/3707)
-* Restore timeupdate/loadedmetadata listeners for duration display ([#3682](https://github.com/videojs/video.js/issues/3682)) ([44ec0e4](https://github.com/videojs/video.js/commit/44ec0e4))
-
-### Chores
-
-* move metadata to hidden folder and update references ([86f0830](https://github.com/videojs/video.js/commit/86f0830))
-* **deps:** add the bundle-collapser browserify plugin ([816291e](https://github.com/videojs/video.js/commit/816291e))
-* refactor redundant code in html5 tech ([#3593](https://github.com/videojs/video.js/issues/3593)) ([6878c21](https://github.com/videojs/video.js/commit/6878c21))
-* refactor redundant or verbose code in player.js ([#3597](https://github.com/videojs/video.js/issues/3597)) ([ae3e277](https://github.com/videojs/video.js/commit/ae3e277))
-* update CHANGELOG automation to use conventional-changelog ([#3669](https://github.com/videojs/video.js/issues/3669)) ([d4e89d2](https://github.com/videojs/video.js/commit/d4e89d2))
-* update object.assign to ^4.0.4 ([08c7f4e](https://github.com/videojs/video.js/commit/08c7f4e))
-* **grunt:** fix getting changelog by switching to  npm-run ([#3687](https://github.com/videojs/video.js/issues/3687)) ([8845bd3](https://github.com/videojs/video.js/commit/8845bd3)), closes [#3683](https://github.com/videojs/video.js/issues/3683)
-* **package:** remove es2015-loose since it's an option for es2015 ([#3629](https://github.com/videojs/video.js/issues/3629)) ([c545acd](https://github.com/videojs/video.js/commit/c545acd))
-* **package:** update grunt-contrib-cssmin to version 1.0.2 ([#3595](https://github.com/videojs/video.js/issues/3595)) ([54e3db5](https://github.com/videojs/video.js/commit/54e3db5))
-* **package:** update grunt-shell to version 2.0.0 ([#3642](https://github.com/videojs/video.js/issues/3642)) ([2032b17](https://github.com/videojs/video.js/commit/2032b17))
-
-### Documentation
-
-* fix broken links in docs index.md ([4063f96](https://github.com/videojs/video.js/commit/4063f96))
-* **options.md:** Remove Bad Apostrophe ([#3677](https://github.com/videojs/video.js/issues/3677)) ([16c8559](https://github.com/videojs/video.js/commit/16c8559))
-* **tech.md:** Add a note on Flash permissions in sandboxed environments ([#3684](https://github.com/videojs/video.js/issues/3684)) ([66922a8](https://github.com/videojs/video.js/commit/66922a8))
-
-### Tests
-
-* **a11y:** add basic accessibility testing using grunt-accessibility ([7d85f27](https://github.com/videojs/video.js/commit/7d85f27))
 
 <a name="5.12.5"></a>
 ## [5.12.5](https://github.com/videojs/video.js/compare/v5.12.4...v5.12.5) (2016-10-19)
@@ -67,7 +31,7 @@
 * **tech.md:** Add a note on Flash permissions in sandboxed environments ([#3684](https://github.com/videojs/video.js/issues/3684)) ([66922a8](https://github.com/videojs/video.js/commit/66922a8))
 
 <a name="5.12.3"></a>
-## [5.12.3](https://github.com/videojs/video.js/compare/v5.10.7...v5.12.3) (2016-10-06)
+## [5.12.3](https://github.com/videojs/video.js/compare/v5.12.2...v5.12.3) (2016-10-06)
 
 ### Features