Update typescript, prettier, tslint -> eslint

[bramkragten]

Proposed change

Updated typescript to 3.8

Using import type now

Updated babel, eslint and prettier to handle that.

Migrated tslint to eslint.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example configuration

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

[iantrich]

...wow...

[bramkragten]

Git didn't allowed me to change the github action in the PR. Not sure if/how the test here should be fixed.

[ludeeus]

Should not be an issue, I have done that multiple times.
Worst case, you could try using GitHub's UI to change it?