Get-GitHubEvent shouldn't use [int] for EventId

[HowardWolosky]

While running UT's, we're seeing the following failure:

Describing Getting an event directly
    Context For getting an event directly

[-] Error occurred in Context block 0ms
        OverflowException: Value was either too large or too small for an Int32.
        PSInvalidCastException: Cannot convert value "2202340851" to type "System.Int32". Error: "Value was either too large or too small for an Int32."
        ArgumentTransformationMetadataException: Cannot convert value "2202340851" to type "System.Int32". Error: "Value was either too large or too small for an Int32."
        ParameterBindingArgumentTransformationException: Cannot process argument transformation on parameter 'EventID'. Cannot convert value "2202340851" to type "System.Int32". Error: "Value was either too large or too small for an Int32."
        at <ScriptBlock>, C:\projects\powershellforgithub\Tests\GitHubEvents.tests.ps1: line 144
        at DescribeImpl, C:\Program Files\WindowsPowerShell\Modules\Pester\4.7.2\Functions\Describe.ps1: line 199