PowerShell ShardManagement is referencing net45 instead of net6.0

[tps-pcaldwell]

The following places are referencing Net 4.5 which I believe Elastic DB Client Library 2.4 now compiles to net 6.0. This is causing an issue with me adopting the PowerShell samples.

https://github.com/Azure/elastic-db-tools/blob/master/Samples/PowerShell/ShardManagement/ShardManagement.psm1#L46

https://github.com/Azure/elastic-db-tools/blob/master/Samples/PowerShell/ShardManagement/ShardManagement.psm1#L57