Api Management Instance Snippet

[egullbrandsson]

Added a small snippet for an Api Management Instance

Contributing a snippet

• [ x ] I have a snippet that is either a single, generic resource or multi resource that uses parent-child syntax
• [ x ] I have checked that there is not an equivalent snippet already submitted
• [ x ] I have used camelCasing unless I have a justification to use another casing style
• [ x ] I have placeholders values that correspond to their property names (e.g. dnsPrefix: 'dnsPrefix'), unless it's a property that MUST be changed or parameterized in order to deploy. In that case, I use 'REQUIRED' e.g. keyData
• [ x ] I have my symbolic name as the first tab stop ($1) in the snippet. e.g. res-aks-cluster.bicep
• [ x ] I have a resource name property equal to "name"

[ghost]

All CLA requirements met.

[MarcusFelling]

Looks great. Thank you for your contribution @emilguden!