Added revoke functionality

Src/Notion.Client/Api/ApiEndpoints.cs

@@ -135,6 +135,7 @@ public static string Create()
         public static class AuthenticationUrls
         {
             public static string CreateToken() => "/v1/oauth/token";
+            public static string RevokeToken() => "/v1/oauth/revoke";
         }
     }
 }

Src/Notion.Client/Api/Authentication/IAuthenticationClient.cs

@@ -18,5 +18,16 @@ Task<CreateTokenResponse> CreateTokenAsync(
             CreateTokenRequest createTokenRequest,
             CancellationToken cancellationToken = default
         );
+
+        /// <summary>
+        /// Revokes an access token.
+        /// </summary>
+        /// <param name="revokeTokenRequest"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        Task RevokeTokenAsync(
+            RevokeTokenRequest revokeTokenRequest,
+            CancellationToken cancellationToken = default
+        );
     }
 }

Src/Notion.Client/Api/Authentication/RevokeToken/AuthenticationClient.cs

@@ -0,0 +1,30 @@
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Notion.Client
+{
+    public sealed partial class AuthenticationClient
+    {
+        public async Task RevokeTokenAsync(
+            RevokeTokenRequest revokeTokenRequest,
+            CancellationToken cancellationToken = default)
+        {
+            var body = (IRevokeTokenBodyParameters)revokeTokenRequest;
+
+            var response = await _client.PostAsync<HttpResponseMessage>(
+                ApiEndpoints.AuthenticationUrls.RevokeToken(),
+                body,
+                cancellationToken: cancellationToken
+            );
+
+            if (!response.IsSuccessStatusCode)
+            {
+                throw new NotionApiException(response.StatusCode,
+                    null,
+                    "None success status code returned from revoke endpoint"
+                );
+            }
+        }
+    }
+}

Src/Notion.Client/Api/Authentication/RevokeToken/Request/IRevokeTokenBodyParameters.cs

@@ -0,0 +1,13 @@
+using Newtonsoft.Json;
+
+namespace Notion.Client
+{
+    public interface IRevokeTokenBodyParameters
+    {
+        /// <summary>
+        /// The token to be revoked.
+        /// </summary>
+        [JsonProperty("token")]
+        string Token { get; set; }
+    }
+}

Src/Notion.Client/Api/Authentication/RevokeToken/Request/RevokeTokenRequest.cs

@@ -0,0 +1,7 @@
+namespace Notion.Client
+{
+    public class RevokeTokenRequest : IRevokeTokenBodyParameters
+    {
+        public string Token { get; set; }
+    }
+}