support/scripts/pkg-stats: fix Python 3.8 deprecation warning

With Python 3.8, the following deprecation warnings are emitted:

/home/thomas/projets/buildroot/./support/scripts/pkg-stats:418: DeprecationWarning: The explicit passing of coroutine objects to asyncio.wait() is deprecated since Python 3.8, and scheduled for removal in Python 3.11.

/home/thomas/projets/buildroot/./support/scripts/pkg-stats:536: DeprecationWarning: The explicit passing of coroutine objects to asyncio.wait() is deprecated since Python 3.8, and scheduled for removal in Python 3.11.

The correct way to pass coroutines is to use asyncio.create_task(),
but this is rather new method (Python 3.7), and using it breaks
compatibility with older Python versions. As suggested at
https://docs.python.org/3/library/asyncio-task.html#asyncio.create_task,
use the more cryptic, but also more compatible asyncio.ensure_future()
method.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
diff --git a/support/scripts/pkg-stats b/support/scripts/pkg-stats
index 99e0ecb..2119f51 100755
--- a/support/scripts/pkg-stats
+++ b/support/scripts/pkg-stats
@@ -434,7 +434,7 @@
     async with aiohttp.ClientSession(connector=connector, trust_env=True) as sess:
         packages = [p for p in packages if p.status['url'][0] == 'ok']
         for pkg in packages:
-            tasks.append(check_url_status(sess, pkg, len(packages)))
+            tasks.append(asyncio.ensure_future(check_url_status(sess, pkg, len(packages))))
         await asyncio.wait(tasks)
 
 
@@ -552,7 +552,7 @@
     async with aiohttp.ClientSession(connector=connector, trust_env=True) as sess:
         packages = [p for p in packages if p.has_valid_infra]
         for pkg in packages:
-            tasks.append(check_package_latest_version_get(sess, pkg, len(packages)))
+            tasks.append(asyncio.ensure_future(check_package_latest_version_get(sess, pkg, len(packages))))
         await asyncio.wait(tasks)