fix(methods): match canvases examples to the docs payload

Author: zimeg

methods/src/main/java/canvases/CanvasesCreate.java

@@ -24,7 +24,6 @@ public static void main(String[] args) throws IOException, SlackApiException {
                         .type("markdown")
                         .markdown("> standalone canvas!")
                         .build())
-                .channelId("C0123456789")
                 .build();
         CanvasesCreateResponse response = methods.canvasesCreate(request);
 

methods/src/main/java/canvases/CanvasesGetContent.java

@@ -18,7 +18,7 @@ public static void main(String[] args) throws IOException, SlackApiException {
 
         // Call the canvases.getContent method
         CanvasesGetContentRequest request = CanvasesGetContentRequest.builder()
-                .canvasId("F1234567890")
+                .canvasId("F1234ABCD")
                 .contentType("markdown")
                 .build();
         CanvasesGetContentResponse response = methods.canvasesGetContent(request);