Describe the bug

Using stacked prop as string value breaks header display. Table header default behavior is like stacked=true at all resolutions

Steps to reproduce the bug

https://codepen.io/MWStudio4/pen/BaBpeGg?&editable=true&editors=101

Expected behavior

As in the documentation using string value in stacked prop should make table stacked in certain resolutions. So if resolution more then in prop table should be original with header

Versions

Libraries:

• BootstrapVue: 2.0.0-rc.28
• Bootstrap: 4.3.1
• Vue: 2.6.10

Environment:

• Device: HP laptop
• OS: Linux KDE Neon (Ubuntu 18.04)
• Browser: Chrome
• Version: 76.0.3809.100

Demo link

CodePen

Additional context