Set version to 2.0 for release.

Added release notes to README.md.

MetaBrainz.MusicBrainz.DiscId/MetaBrainz.MusicBrainz.DiscId.csproj

@@ -5,8 +5,7 @@
     <Title>MusicBrainz DiscID Library</Title>
     <Description>This package provides classes for accessing information about a CD (its MusicBrainz Disc ID, EAN/ISRC values, CD-TEXT info, ...).</Description>
     <PackageTags>MusicBrainz discid audio cd cd-text isrc upc ean libdiscid</PackageTags>
-    <Version>2.0.0-pre</Version>
-    <PackageReleaseNotes/>
+    <Version>2.0.0</Version>
   </PropertyGroup>
 
   <PropertyGroup>

README.md

@@ -8,3 +8,22 @@ However, things should work regardless of the host implementation (.NET Framewor
 
 Support for Solaris is unlikely, because there does not seem to be any easy way to get Mono to work on it.
 Support for OSX is similarly unlikely, because I have no access to a system.
+
+## Release Notes
+
+### v2.0 (2020-03-21)
+
+- Target .NET Standard 2.0 and 2.1, .NET Core 2.1 and 3.1 (the current LTS releases) and .NET Framework 4.6.1, 4.7.2 and 4.8.
+- Minor doc fixes.
+- Use nullable reference types.
+
+### v1.0.1 (2018-11-15)
+
+Corrected the build so that the IntelliSense XML documentation is property built and packaged.
+
+### v1.0 (2018-01-21)
+
+First official release.
+
+- Dropped support for .NET framework versions before 4.0 (and 4.0 may be dropped in a later version); this allows for builds using .NET Core (which cannot target 2.0/3.5).
+- Added support for .NET Standard 2.0; the only unsupported API is RawImage.Decode() (because System.Drawing.Image is not available).

appveyor.yml

@@ -1,4 +1,4 @@
-version: 2.0.0.{build}-appveyor
+version: 2.0.0
 image: Visual Studio 2019
 configuration: Debug
 install: