Bump BouncyCastle.NetCore in /src/LtiAdvantage.AspNetCore

Bumps [BouncyCastle.NetCore](https://github.com/chrishaly/bc-csharp) from 1.8.3 to 1.9.0.
- [Commits](https://github.com/chrishaly/bc-csharp/commits)

---
updated-dependencies:
- dependency-name: BouncyCastle.NetCore
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

src/LtiAdvantage/LtiAdvantage.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>.NET Core library with IMS LTIAdvantage support for Tool Consumer and Tool Provider applications.</Description>
@@ -23,7 +23,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="BouncyCastle.NetCore" Version="1.8.3" />
+    <PackageReference Include="BouncyCastle.NetCore" Version="1.9.0" />
     <PackageReference Include="MinVer" Version="2.3.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>