Microsoft.Migrate throws a BCP081: Resource type "Microsoft.Migrate/migrateProjects/solutions@2020-05-01" does not have types available.

**Bicep version**
bicep --version
Bicep CLI version 0.5.6 (5f2f88f0f0)

**Describe the bug**
MigrateProject samples on MS's doc site reference "Microsoft.Migrate/migrateProjects/solutions@2020-05-01"

* https://docs.microsoft.com/en-us/azure/templates/microsoft.migrate/2020-05-01/migrateprojects?tabs=bicep
* https://docs.microsoft.com/en-us/azure/migrate/quickstart-create-migrate-project

However, when you use that in a Bicep file it indicates types are not available:

``` bicep
resource migrateProject 'Microsoft.Migrate/migrateProjects@2020-05-01' = {
name: 'NameOfProject'
location: 'centralus'
tags: {
'Migrate Project': 'NameOfProject'
}
properties: {}
}
```

```
C:\temp\migrateproject.bicep(12,3) : Warning BCP187: The property "tags" does not exist in the resource definition, although it might still be valid. If this is an inaccuracy in the documentation, please report it to the Bicep Team. [https://aka.ms/bicep-type-issues]
C:\temp\migrateproject.bicep(16,28) : Warning BCP081: Resource type "Microsoft.Migrate/migrateProjects/solutions@2020-05-01" does not have types available.
```

In addition, the `tags` property is indicated as"

Warning BCP187: The property "tags" does not exist in the resource definition, although it might still be valid.

**To Reproduce**
Steps to reproduce the behavior:

Simple Bicep file:

``` bicep
resource migrateProject 'Microsoft.Migrate/migrateProjects@2020-05-01' = {
name: 'NameOfProject'
location: 'centralus'
tags: {
'Migrate Project': 'NameOfProject'
}
properties: {}
}
```

**Additional context**
Add any other context about the problem here.

Start with the simple Bicep file and the Microsoft.Migrate documentation links in the report, then reproduce the warnings using Bicep CLI version 0.5.6. Trace how the Microsoft.Migrate/migrateProjects resource type is resolved and verify that the 2020-05-01 type and tags property are recognized without BCP081 or BCP187 warnings.

Written by the indexing model from the issue text.