Bump IdentityServerVersion from 7.0.6 to 7.0.8

Bumps `IdentityServerVersion` from 7.0.6 to 7.0.8.

Updates `Duende.IdentityServer` from 7.0.6 to 7.0.8
- [Release notes](https://github.com/DuendeSoftware/IdentityServer/releases)
- [Commits](DuendeSoftware/products@7.0.6...7.0.8)

Updates `Microsoft.AspNetCore.Authentication.OpenIdConnect` from 8.0.1 to 8.0.3
- [Release notes](https://github.com/dotnet/aspnetcore/releases)
- [Changelog](https://github.com/dotnet/aspnetcore/blob/main/docs/ReleasePlanning.md)
- [Commits](dotnet/aspnetcore@v8.0.1...v8.0.3)

---
updated-dependencies:
- dependency-name: Duende.IdentityServer
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: Microsoft.AspNetCore.Authentication.OpenIdConnect
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Directory.Build.targets

@@ -1,9 +1,9 @@
 <Project>
     <PropertyGroup Condition=" '$(TargetFramework)' == 'net8.0'">
-        <FrameworkVersion>8.0.1</FrameworkVersion>
+        <FrameworkVersion>8.0.3</FrameworkVersion>
         <ExtensionsVersion>8.0.0</ExtensionsVersion>
         <WilsonVersion>7.1.2</WilsonVersion>
-        <IdentityServerVersion>7.0.6</IdentityServerVersion>
+        <IdentityServerVersion>7.0.8</IdentityServerVersion>
     </PropertyGroup>
 
     <ItemGroup>