EsrpSign.yml@ComplianceRepo could leverage yaml arrays

Currently `pattern` is a string with commas in it:
```
pattern: 'Microsoft.PowerShell.*.dll,Microsoft.PowerShell.*.psd1,Microsoft.PowerShell.*.psm1'
```

It would be nice if this could be:

```
pattern:
  - 'Microsoft.PowerShell.*.dll'
  - 'Microsoft.PowerShell.*.psd1'
  - 'Microsoft.PowerShell.*.psm1'
```

to align better with YAML.