3.0.0-beta

• The polyfill extension methods have moved to the namespace FolkerKinzel.Strings.Polyfills.
  The namespace was needed, because some of the polyfill extension methods cause conflicts with
  existing extension methods from System.MemoryExtensions when used in a .NET Core 3.1 app. The
  new namespace will help to resolve such conflicts.
  This is a breaking change that requires a new Major version, because the new namespace has to be
  published in existing code to make use of the polyfills.

• New Polyfills for .NET Framework 4.5, .NET Standard 2.0 and .NET Standard 2.1:

public static ReadOnlyMemory<char> Trim(this ReadOnlyMemory<char> memory);
public static ReadOnlyMemory<char> TrimStart(this ReadOnlyMemory<char> memory);
public static ReadOnlyMemory<char> TrimEnd(this ReadOnlyMemory<char> memory);

• New Polyfills for .NET Framework 4.5, .NET Standard 2.0:

public static bool Contains(this string s, char value);
public static StringBuilder Append(this StringBuilder builder, ReadOnlySpan<char> value);

• Additional overloads of the StringBuilder.Trim extension methods:

public static StringBuilder Trim(this StringBuilder builder, ReadOnlySpan<char> trimChars);
public static StringBuilder TrimStart(this StringBuilder builder, ReadOnlySpan<char> trimChars);
public static StringBuilder TrimEnd(this StringBuilder builder, ReadOnlySpan<char> trimChars);

• Additional extension methods for the System.String class:

public static string Trim(this string s, ReadOnlySpan<char> trimChars);
public static string TrimStart(this string s, ReadOnlySpan<char> trimChars);
public static string TrimEnd(this string s, ReadOnlySpan<char> trimChars);

• The Polyfill for ReadOnlySpan<T> is now specalized for ReadOnlySpan<Char>
  in order to solve a conflict in .NET Core 3.1:

public static bool Contains(this ReadOnlySpan<char> span, char value);

• The CLSCompliantAttribute has been added.