pkg-merge-upstream-to-downstreams: Fix typos

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

package-source-builder/overlay/usr/bin/apertis-pkg-merge-upstream-to-downstreams

@@ -87,7 +87,7 @@ def ensure_downstream_branch(project_url, downstream, dry_run):
       netloc=netloc_no_auth,
   )
   project_branches_url = url.geturl()
-  # TODO: add `ci.skip` once it is avaliable from the API
+  # TODO: add `ci.skip` once it is available from the API
   data = {"branch": urllib.parse.quote(downstream), "ref": downstream_commit}
   print(f"POST'ing to {project_branches_url}: {data}")
   req = urllib.request.Request(
@@ -136,11 +136,11 @@ def main():
   parser.add_argument('--upstream', dest='upstream', type=str,
                       required=True, help='the upstream branch (e.g. debian/buster)')
   parser.add_argument('--downstreams', dest='downstreams', type=str,
-                      required=True, help='downstream branches, colon seperate (e.g.  apertis/v2020dev0:apertis/v2019)')
+                      required=True, help='downstream branches, colon separate (e.g.  apertis/v2020dev0:apertis/v2019)')
   parser.add_argument('--rebase-range', dest='rebase_range', type=str,
                       help='rebase changes from this range as well (e.g. apertis/v2021..downstream/v2021 when targeting downstream/v2022dev0)')
   parser.add_argument('--stable', dest='stable', type=str, default='',
-                      help='stable branches, colon seperate (e.g.  apertis/v2021:apertis/v2020)')
+                      help='stable branches, colon separate (e.g.  apertis/v2021:apertis/v2020)')
   parser.add_argument('--local-version-suffix', dest="local_suffix", type=str, default="+apertis", help='the local version suffix to be used in new changelog entries')
   parser.add_argument('project_url', type=str, help='git project url to push updates to')
   parser.add_argument('--auto-merge', dest='auto_merge', type=str, default='',