fix changelog open mode

Stefano Torresi · Stefano Torresi · commit 8e4544a59c0d · 2020-02-28T14:06:06.000+01:00
diff --git a/.ci/gh_release_to_obs_changeset.py b/.ci/gh_release_to_obs_changeset.py
@@ -55,7 +55,7 @@
     temp.seek(0)
 
     if args.file:
-        with open(args.file, "r") as prev:
+        with open(args.file, "a+") as prev:
             old = prev.read()
         with open(args.file, "w") as new:
             for line in temp:
