Fix rate limiting from pygithub.RateLimitExceededException (adafruit#263

)

The "core rate limit reset" time is in UTC, while github actions
may be running in another timezone, such as PST. The below example
was run in my local timezone, CST:

```python
>>> import os, datetime
>>> import github as pygithub
>>> GH_INTERFACE = pygithub.Github(os.environ.get("ADABOT_GITHUB_ACCESS_TOKEN"))
>>> GH_INTERFACE.get_rate_limit().core.reset - datetime.datetime.now()
datetime.timedelta(seconds=24750, microseconds=356986)
>>> GH_INTERFACE.get_rate_limit().core.reset - datetime.datetime.utcnow()
datetime.timedelta(seconds=3147, microseconds=87271)
```

Use utcnow() instead of now() so that the sleep is for the correct
duration.

(utcnow is deprecated, but the correct alternative, `now(tz=datetime.timezone.utc)`
does not work: `GH_INTERFACE.get_rate_limit().core.reset` is a naive
timestamp and can't be compared with a tz-aware object)

adabot/circuitpython_libraries.py

@@ -257,7 +257,7 @@ def run_library_checks(validators, kw_args, error_depth):
             break
         except pygithub.RateLimitExceededException:
             core_rate_limit_reset = GH_INTERFACE.get_rate_limit().core.reset
-            sleep_time = core_rate_limit_reset - datetime.datetime.now()
+            sleep_time = core_rate_limit_reset - datetime.datetime.utcnow()
             logging.warning("Rate Limit will reset at: %s", core_rate_limit_reset)
             time.sleep(sleep_time.seconds)
             continue

adabot/lib/bundle_announcer.py

@@ -80,7 +80,7 @@ def get_bundle_updates(full_repo_name: str) -> Tuple[Set[RepoResult], Set[RepoRe
 
         except pygithub.RateLimitExceededException:
             core_rate_limit_reset = GH_INTERFACE.get_rate_limit().core.reset
-            sleep_time = core_rate_limit_reset - datetime.datetime.now()
+            sleep_time = core_rate_limit_reset - datetime.datetime.utcnow()
             logging.warning("Rate Limit will reset at: %s", core_rate_limit_reset)
             time.sleep(sleep_time.seconds)
             continue

adabot/lib/circuitpython_library_validators.py

@@ -916,7 +916,7 @@ def validate_readthedocs(self, repo):
                 break
             except pygithub.RateLimitExceededException:
                 core_rate_limit_reset = GH_INTERFACE.get_rate_limit().core.reset
-                sleep_time = core_rate_limit_reset - datetime.datetime.now()
+                sleep_time = core_rate_limit_reset - datetime.datetime.utcnow()
                 logging.warning("Rate Limit will reset at: %s", core_rate_limit_reset)
                 time.sleep(sleep_time.seconds)
                 continue
@@ -1275,7 +1275,7 @@ def validate_actions_state(self, repo):
                 return []
             except pygithub.RateLimitExceededException:
                 core_rate_limit_reset = GH_INTERFACE.get_rate_limit().core.reset
-                sleep_time = core_rate_limit_reset - datetime.datetime.now()
+                sleep_time = core_rate_limit_reset - datetime.datetime.utcnow()
                 logging.warning("Rate Limit will reset at: %s", core_rate_limit_reset)
                 time.sleep(sleep_time.seconds)