Update frameworks.md - add .NET Framework 4.8.1 (#39396)

Author: Saibamen

docs/standard/frameworks.md

@@ -30,7 +30,7 @@ The following table defines the most common target frameworks, how they're refer
 | .NET 5           | 5                           | net5.0                         | 2.1                                     |
 | .NET Standard    | 2.1                         | netstandard2.1                 | N/A                                     |
 | .NET Core        | 3.1                         | netcoreapp3.1                  | 2.1                                     |
-| .NET Framework   | 4.8                         | net48                          | 2.0                                     |
+| .NET Framework   | 4.8.1                       | net481                         | 2.0                                     |
 
 ## Supported target frameworks
 
@@ -40,7 +40,7 @@ A target framework is typically referenced by a TFM. The following table shows t
 | -------------------------- | --- |
 | .NET 5+ (and .NET Core)    | netcoreapp1.0<br>netcoreapp1.1<br>netcoreapp2.0<br>netcoreapp2.1<br>netcoreapp2.2<br>netcoreapp3.0<br>netcoreapp3.1<br>net5.0*<br>net6.0*<br>net7.0*<br>net8.0* |
 | .NET Standard              | netstandard1.0<br>netstandard1.1<br>netstandard1.2<br>netstandard1.3<br>netstandard1.4<br>netstandard1.5<br>netstandard1.6<br>netstandard2.0<br>netstandard2.1 |
-| .NET Framework             | net11<br>net20<br>net35<br>net40<br>net403<br>net45<br>net451<br>net452<br>net46<br>net461<br>net462<br>net47<br>net471<br>net472<br>net48 |
+| .NET Framework             | net11<br>net20<br>net35<br>net40<br>net403<br>net45<br>net451<br>net452<br>net46<br>net461<br>net462<br>net47<br>net471<br>net472<br>net48<br>net481 |
 | Windows Store              | netcore [netcore45]<br>netcore45 [win] [win8]<br>netcore451 [win81] |
 | .NET Micro Framework       | netmf |
 | Silverlight                | sl4<br>sl5 |