Only retry on 403 FORBIDDEN or 429 TOO_MANY_REQUESTS

GitHub's docs clearly state that it will only respond with 403 or 429
if you exceed the rate limit.
https://docs.github.com/en/rest/using-the-rest-api/rate-limits-for-the-rest-api?apiVersion=2022-11-28#exceeding-the-rate-limit

The current logic was triggering a retry for all non-success responses.
In some situations (like expected 404 responses), this was causing
triagebot to send 3 extra needless requests.

Author: ehuss

src/github.rs

@@ -51,7 +51,10 @@ impl GithubClient {
         const REMAINING: &str = "X-RateLimit-Remaining";
         const RESET: &str = "X-RateLimit-Reset";
 
-        if resp.status().is_success() {
+        if !matches!(
+            resp.status(),
+            StatusCode::FORBIDDEN | StatusCode::TOO_MANY_REQUESTS
+        ) {
             return None;
         }
 
@@ -60,12 +63,6 @@ impl GithubClient {
             return None;
         }
 
-        // Weird github api behavior. It asks us to retry but also has a remaining count above 1
-        // Try again immediately and hope for the best...
-        if headers[REMAINING] != "0" {
-            return Some(Duration::from_secs(0));
-        }
-
         let reset_time = headers[RESET].to_str().unwrap().parse::<u64>().unwrap();
         Some(Duration::from_secs(Self::calc_sleep(reset_time) + 10))
     }