Upgrade azure_identity and azure_core to latest 0.20 version

**Is your feature request related to a problem? Please describe.**
A lot of other sdks for rust have started using the 0.20 versions for azure_identity and azure_core. Because of the way cargo handles conflicts, when a project includes both the azure-kusto-XXX and some other sdk that uses the 0.20 versions, compilation fails.

**Describe the solution you'd like**
Upgrade the kusto rust sdks to 0.20 versions of azure_identity and azure_core

**Describe alternatives you've considered**
None

**Additional context**
NA