docs: update alpine installtion for alpine > 3.13

Created by: solidnerd

Signed-off-by: solidnerd niclas@mietz.io

Description

Related Issue

Resolves #[issue_number]

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation
• Chore (Related to CI or Packaging to platforms)