Bump Microsoft.IdentityModel.Protocols.OpenIdConnect from 8.18.0 to 8.21.0

---
updated-dependencies:
- dependency-name: Microsoft.IdentityModel.Protocols.OpenIdConnect
  dependency-version: 8.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

src/Microsoft.Graph.Core/Microsoft.Graph.Core.csproj

@@ -65,7 +65,7 @@
   </ItemGroup>
   <!-- Verify all PackageReferences here are up to date before releasing new version -->
   <ItemGroup>
-    <PackageReference Include="Microsoft.IdentityModel.Protocols.OpenIdConnect" Version="8.18.0" />
+    <PackageReference Include="Microsoft.IdentityModel.Protocols.OpenIdConnect" Version="8.21.0" />
     <PackageReference Include="Microsoft.IdentityModel.Validators" Version="8.18.0" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="10.0.203" PrivateAssets="All" />
     <PackageReference Include="Microsoft.Kiota.Abstractions" Version="2.0.0" />