fix(html5): `<audio>` and `<video>` allows `<track>` and `<source>` transparently

fixes #104
12 jobs for bugfix/issue-104-video-source in 11 minutes and 20 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Prepare
passed #1010089908
NPM

00:03:01

 
  Build
passed #1010089909
Build

00:01:41

 
  Test
passed #1010089911
Changelog

00:01:05

passed #1010089915
Docs

00:02:45

passed #1010089912
ESLint

00:01:37

passed #1010089913
Jest

00:04:02

98.35%
passed #1010089914
Prettier

00:01:23

passed #1010089910
license_scanning

00:01:29

 
  Compatibility
passed #1010089916
Node 10.x (LTS)

00:06:00

passed #1010089917
Node 12.x (LTS)

00:05:49

passed #1010089918
Node 14.x (LTS)

00:05:36

passed #1010089920
Node 15.x (current)

00:06:33