docs(provider): Update IdentityServer 4 demo configuration (#1932)

Author: Thisen

www/docs/providers/identity-server4.md

@@ -7,16 +7,15 @@ title: IdentityServer4
 
 https://identityserver4.readthedocs.io/en/latest/
 
-
 ## Example
 
 ```js
 import Providers from `next-auth/providers`
 ...
 providers: [
   Providers.IdentityServer4({
-    id: "identity-server4", 
-    name: "IdentityServer4", 
+    id: "identity-server4",
+    name: "IdentityServer4",
     scope: "openid profile email api offline_access", // Allowed Scopes
     domain:  process.env.IdentityServer4_Domain,
     clientId: process.env.IdentityServer4_CLIENT_ID,
@@ -33,18 +32,20 @@ The configuration below is for the demo server at https://demo.identityserver.io
 If you want to try it out, you can copy and paste the configuration below.
 
 You can sign in to the demo service with either <b>bob/bob</b> or <b>alice/alice</b>.
- 
+
 ```js
 import Providers from `next-auth/providers`
 ...
 providers: [
   Providers.IdentityServer4({
-    id: "demo-identity-server",  
-    name: "Demo IdentityServer4", 
-    scope: "openid profile email api offline_access", 
+    id: "demo-identity-server",
+    name: "Demo IdentityServer4",
+    scope: "openid profile email api offline_access",
     domain:  "demo.identityserver.io",
-    clientId: "server.code",
-    clientSecret: "secret"
+    clientId: "interactive.confidential",
+    clientSecret: "secret",
+    protection: "pkce"
   })
 }
 ...
+```