Bump Azure.Identity from 1.13.2 to 1.21.0 (#378)

---
updated-dependencies:
- dependency-name: Azure.Identity
  dependency-version: 1.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]

GraphOrgExample/GraphOrgExample.csproj

@@ -5,7 +5,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Azure.Identity" Version="1.13.2" />
+    <PackageReference Include="Azure.Identity" Version="1.21.0" />
     <PackageReference Include="Microsoft.Graph" Version="5.105.0" />
     <PackageReference Include="Microsoft.Identity.Client" Version="4.83.3" />
     <PackageReference Include="Microsoft.Identity.Web.MicrosoftGraph" Version="3.6.1" />