Update Microsoft.Data.SqlClient dependency to v3.0.0

[cgillum]

Release notes: https://github.com/dotnet/SqlClient/blob/main/release-notes/3.0/3.0.0.md

Notable changes:

• This version has built-in support for Azure managed identities and could potentially allow us to simplify our own support for this.
• This version has built-in automatic retry support for transient errors (in preview). This could potentially replace our customer implementation.

[usemam]

@cgillum
Please take a look at PR #33 - it essentially reverts changes that introduced Azure Managed Identity support and adds reference to Microsoft.Data.SqlClient package v3.0.0

[cgillum]

PR merged! This will go out with the v0.10.0 release.