Update release notes

Author: NN---

CodeJam.Main/Readme.txt

@@ -3,6 +3,7 @@
 
 What's new in 4.0.0-beta1
 -------------------------
-* Add C# 8+ nullability markup
-* Remove JB's NotNull/CanBeNull markup
-* Remove deprecated targets
+* Add C# nullability markup.
+* Remove JetBrains nullability markup: NotNull/CanBeNull/ItemNotNull.
+* Remove deprecated targets. Supporting: .NET 3.5+, .NET Standard 2.0+, .NET Core 3.1+.
+* Fixed Range string representation bug.

README.md

@@ -38,25 +38,25 @@ CodeJam.PerfTests is performance testing framework for .Net projects.
 It allows to compare multiple implementations by execution time (*~memory limits coming soon~*), to annotate test methods
 with timing limits and to check the limits each time the test is run.
 
-### .NET Standard 1.6, 1.5 support
+### .NET Standard 1.6, 1.5 support (supported dropped in 4.0)
 
 Almost all features are supported. Functionality not supported:
 
 * XmlAttributeReader
 
-### .NET Core 1.1, 1.0 support
+### .NET Core 1.1, 1.0 support (supported dropped in 4.0)
 
 Almost all features are supported. Functionality not supported:
 
 * XmlAttributeReader
 
-### .NET Framework 2.0 support
+### .NET Framework 2.0 support (supported dropped in 4.0)
 
 .NET Framework 2.0 support is limited. Functionality not supported in addition to .NET Framework 3.5 limitations:
 
 * LINQ to XML extensions - .NET 2.0 doesn't have LINQ XML related classes
 
-### .NET Framework 3.0 support
+### .NET Framework 3.0 support (supported dropped in 4.0)
 
 .NET Framework 3.0 support is limited. Functionality not supported in addition to .NET Framework 3.5 limitations: