Merge pull request #1960 from timdeschryver/migration-docs

docs: add migration docs

docs/site/angular-auth-oidc-client/docs/migrations/v15-to-v16.md

@@ -1,5 +1,5 @@
 ---
-sidebar_position: 6
+sidebar_position: 95
 ---
 
 # Version 15 to 16

docs/site/angular-auth-oidc-client/docs/migrations/v16-to-v17.md

@@ -0,0 +1,9 @@
+---
+sidebar_position: 94
+---
+
+# Version 16 to 17
+
+## TL;DR: Breaking Changes
+
+- There should be no breaking changes in this version.

docs/site/angular-auth-oidc-client/docs/migrations/v17-to-v18.md

@@ -0,0 +1,41 @@
+---
+sidebar_position: 93
+---
+
+# Version 17 to 18
+
+## TL;DR: Breaking Changes
+
+- Dropped support for Angular 15
+
+## TL;DR: New Features
+
+- Add new standalone/functional API's
+
+## Dropped support for Angular 15
+
+Angular 15 support is dropped because we want to make us of [Signals](https://angular.dev/guide/signals).
+
+## Add `authenticated` and `userData` Signals to the `OidcSecurityService` service
+
+```ts
+@Component({
+  selector: 'app-root',
+  template: `
+    @if (authenticated().isAuthenticated) {
+    <pre>{{ userData() | json }}</pre>
+    } @else {
+    <div>You are not authenticated.</div>
+    }
+  `,
+})
+export class AppComponent {
+  private readonly oidcSecurityService = inject(OidcSecurityService);
+
+  // Signal containing authenticated state
+  protected readonly authenticated = this.oidcSecurityService.authenticated;
+
+  // Signal containing user data
+  protected readonly userData = this.oidcSecurityService.userData;
+}
+```