fix: database default collation name

[kevin-fitlg]

The default value for variable databases_collation has a wrong casing. It is set to all uppercase letters and AzureRM API detects a diff when the collation is set via portal (like a restored database);

Even if you create a database via portal, it does not accept wrong casing.

Type of change

• [x] 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 not work as expected)
• [ ] This change requires a documentation update

Changes proposed in this pull request

• sets the default collation with correct casing

@claranet/fr-azure-reviewers

[kevin-fitlg]

That was quick :) Thanks team