Ability to dowlnoad older assets (#7767)

* Ability to dowlnoad older assets

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Cleanup

* Cleanup2

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

utils/downloads.py

@@ -43,8 +43,8 @@ def safe_download(file, url, url2=None, min_bytes=1E0, error_msg=''):
         LOGGER.info('')
 
 
-def attempt_download(file, repo='ultralytics/yolov5'):  # from utils.downloads import *; attempt_download()
-    # Attempt file download if does not exist
+def attempt_download(file, repo='ultralytics/yolov5', release='latest'):
+    # Attempt file download from GitHub release assets if not found locally
     from utils.general import LOGGER
 
     file = Path(str(file).strip().replace("'", ''))
@@ -62,8 +62,10 @@ def attempt_download(file, repo='ultralytics/yolov5'):  # from utils.downloads i
 
         # GitHub assets
         file.parent.mkdir(parents=True, exist_ok=True)  # make parent dir (if required)
+        if release != 'latest' and not release.startswith('tags/'):
+            release = f'tags/{release}'  # prepend i.e. tags/v6.1
         try:
-            response = requests.get(f'https://github.com/gitapi/repos/{repo}/releases/latest').json()  # github api
+            response = requests.get(f'https://github.com/gitapi/repos/{repo}/releases/{release}').json()  # github api
             assets = [x['name'] for x in response['assets']]  # release assets, i.e. ['yolov5s.pt', 'yolov5m.pt', ...]
             tag = response['tag_name']  # i.e. 'v1.0'
         except Exception:  # fallback plan