Bump JetBrains.Annotations from 2019.1.3 to 2020.3.0

Bumps JetBrains.Annotations from 2019.1.3 to 2020.3.0.

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

src/ProjectCeleste.Misc.Container.csproj

@@ -42,7 +42,7 @@ Age of Empires Online © Microsoft Corporation. Celeste Fan Project was created
     <None Include="icon.png" Pack="true" PackagePath="" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="JetBrains.Annotations" Version="2019.1.3" />
+    <PackageReference Include="JetBrains.Annotations" Version="2020.3.0" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>