Bump Microsoft.EntityFrameworkCore from 3.1.5 to 3.1.6 (#63)

Bumps [Microsoft.EntityFrameworkCore](https://github.com/dotnet/efcore) from 3.1.5 to 3.1.6.
- [Release notes](https://github.com/dotnet/efcore/releases)
- [Commits](dotnet/efcore@v3.1.5...v3.1.6)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

MiraiNotes.Shared/MiraiNotes.Shared.csproj

@@ -25,7 +25,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.AppCenter.Analytics" Version="3.3.0" />
     <PackageReference Include="Microsoft.AppCenter.Crashes" Version="3.3.0" />
-    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.1.5" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.1.6" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="3.1.5">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>