Bump Azure.Identity from 1.2.0-preview.2 to 1.2.0

Bumps [Azure.Identity](https://github.com/Azure/azure-sdk-for-net) from 1.2.0-preview.2 to 1.2.0.
- [Release notes](https://github.com/Azure/azure-sdk-for-net/releases)
- [Commits](Azure/azure-sdk-for-net@Azure.Identity_1.2.0-preview.2...Azure.Identity_1.2.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

NuGetKeyVaultSignTool/NuGetKeyVaultSignTool.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Azure.Identity" Version="1.2.0-preview.2" />
+    <PackageReference Include="Azure.Identity" Version="1.2.0" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="3.1.7" />
     <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="3.1.7" />
     <PackageReference Include="Microsoft.Extensions.CommandLineUtils" Version="1.1.1" />