Bump System.IdentityModel.Tokens.Jwt in /src/LtiAdvantage.IdentityModel

Bumps [System.IdentityModel.Tokens.Jwt](https://github.com/AzureAD/azure-activedirectory-identitymodel-extensions-for-dotnet) from 7.1.2 to 8.1.0.
- [Release notes](https://github.com/AzureAD/azure-activedirectory-identitymodel-extensions-for-dotnet/releases)
- [Changelog](https://github.com/AzureAD/azure-activedirectory-identitymodel-extensions-for-dotnet/blob/dev/CHANGELOG.md)
- [Commits](AzureAD/azure-activedirectory-identitymodel-extensions-for-dotnet@7.1.2...8.1.0)

---
updated-dependencies:
- dependency-name: System.IdentityModel.Tokens.Jwt
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

src/LtiAdvantage.IdentityModel/LtiAdvantage.IdentityModel.csproj

@@ -21,7 +21,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="7.1.2" />
+    <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="8.1.0" />
   </ItemGroup>
 
 </Project>