Try to avoid hitting secondary rate limit when opening issues

GitHub employs a secondary rate limit for actions that can trigger
notifications, such as opening a new issue. To avoid hitting this
limit, they recommend [1] waiting at least one second between each
request.

This commit attempts to comply with this guidance by adding a
one-second sleep prior to each POST request that opens an issue.

Closes gh-29879

[1] https://docs.github.com/en/rest/guides/best-practices-for-integrators#dealing-with-secondary-rate-limits

buildSrc/src/main/java/org/springframework/boot/build/bom/bomr/github/StandardGitHubRepository.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -50,6 +50,12 @@ final class StandardGitHubRepository implements GitHubRepository {
 			requestBody.put("labels", labels);
 		}
 		requestBody.put("body", body);
+		try {
+			Thread.sleep(1000);
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+		}
 		ResponseEntity<Map> response = this.rest.postForEntity("issues", requestBody, Map.class);
 		return (Integer) response.getBody().get("number");
 	}