Replace .NET Core 3.0 version references by 3.X

This implies support for .NET 3.0.* and 3.1.*

Author: jawn

articles/azure-monitor/app/asp-net-core.md

@@ -28,7 +28,7 @@ The [Application Insights SDK for ASP.NET Core](https://nuget.org/packages/Micro
 * **IDE**: Visual Studio, VS Code, or command line.
 
 > [!NOTE]
-> If you are using ASP.NET Core 3.0 along with Application Insights, please use the [2.8.0](https://www.nuget.org/packages/Microsoft.ApplicationInsights.AspNetCore/2.8.0) version or higher. This is the only version that supports ASP.NET Core 3.0.
+> If you are using ASP.NET Core 3.X along with Application Insights, please use the [2.8.0](https://www.nuget.org/packages/Microsoft.ApplicationInsights.AspNetCore/2.8.0) version or higher. This is the only version that supports ASP.NET Core 3.X.
 
 ## Prerequisites
 
@@ -141,7 +141,7 @@ Support for [performance counters](https://azure.microsoft.com/documentation/art
 
 ### EventCounter
 
-`EventCounterCollectionModule` is enabled by default, and it will collect a default set of counters from .NET Core 3.0 apps. The [EventCounter](eventcounters.md) tutorial lists the default set of counters collected. It also has instructions on customizing the list.
+`EventCounterCollectionModule` is enabled by default, and it will collect a default set of counters from .NET Core 3.X apps. The [EventCounter](eventcounters.md) tutorial lists the default set of counters collected. It also has instructions on customizing the list.
 
 ## Enable client-side telemetry for web applications
 
@@ -347,11 +347,11 @@ The above does not prevent any auto collection modules from collecting telemetry
 
 ## Frequently asked questions
 
-### Does Application Insights support ASP.NET Core 3.0?
+### Does Application Insights support ASP.NET Core 3.X?
 
-Yes. Update to [Application Insights SDK for ASP.NET Core](https://nuget.org/packages/Microsoft.ApplicationInsights.AspNetCore) version 2.8.0 or higher. Older versions of the SDK do not support ASP.NET Core 3.0.
+Yes. Update to [Application Insights SDK for ASP.NET Core](https://nuget.org/packages/Microsoft.ApplicationInsights.AspNetCore) version 2.8.0 or higher. Older versions of the SDK do not support ASP.NET Core 3.X.
 
-Also, if you are using Visual Studio based instructions from [here](#enable-application-insights-server-side-telemetry-visual-studio), update to the latest version of Visual Studio 2019 (16.3.0) to onboard. Previous versions of Visual Studio do not support automatic onboarding for ASP.NET Core 3.0 apps.
+Also, if you are using Visual Studio based instructions from [here](#enable-application-insights-server-side-telemetry-visual-studio), update to the latest version of Visual Studio 2019 (16.3.0) to onboard. Previous versions of Visual Studio do not support automatic onboarding for ASP.NET Core 3.X apps.
 
 ### How can I track telemetry that's not automatically collected?
 
@@ -384,7 +384,7 @@ For more information about custom data reporting in Application Insights, see [A
 
 ### Some Visual Studio templates used the UseApplicationInsights() extension method on IWebHostBuilder to enable Application Insights. Is this usage still valid?
 
-While the extension method `UseApplicationInsights()` is still supported, it is marked obsolete in Application Insights SDK version 2.8.0 onwards. It will be removed in the next major version of the SDK. The recommended way to enable Application Insights telemetry is by using `AddApplicationInsightsTelemetry()` because it provides overloads to control some configuration. Also, in ASP.NET Core 3.0 apps, `services.AddApplicationInsightsTelemetry()` is the only way to enable application insights.
+While the extension method `UseApplicationInsights()` is still supported, it is marked obsolete in Application Insights SDK version 2.8.0 onwards. It will be removed in the next major version of the SDK. The recommended way to enable Application Insights telemetry is by using `AddApplicationInsightsTelemetry()` because it provides overloads to control some configuration. Also, in ASP.NET Core 3.X apps, `services.AddApplicationInsightsTelemetry()` is the only way to enable application insights.
 
 ### I'm deploying my ASP.NET Core application to Web Apps. Should I still enable the Application Insights extension from Web Apps?
 
@@ -431,9 +431,9 @@ using Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel;
     }
 ```
 
-### Is this SDK supported for the new .NET Core 3.0 Worker Service template applications?
+### Is this SDK supported for the new .NET Core 3.X Worker Service template applications?
 
-This SDK requires `HttpContext`, and hence does not work in any non-HTTP applications, including the .NET Core 3.0 Worker Service applications. Refer to [this](worker-service.md) document for enabling application insights in such applications, using the newly released Microsoft.ApplicationInsights.WorkerService SDK.
+This SDK requires `HttpContext`, and hence does not work in any non-HTTP applications, including the .NET Core 3.X Worker Service applications. Refer to [this](worker-service.md) document for enabling application insights in such applications, using the newly released Microsoft.ApplicationInsights.WorkerService SDK.
 
 ## Open-source SDK