Pin proctoring plugin code

We intend for subsequent versions to be reviewed manually before
finding their way into edx-platform proper; this prevents subsequent
releases from finding their way in without human intervention

requirements/edx/base.in

@@ -79,7 +79,7 @@ edx-milestones
 edx-oauth2-provider
 edx-organizations
 edx-proctoring>=1.6.0
-edx-proctoring-proctortrack
+edx-proctoring-proctortrack==1.0.4  # Intentionally and permanently pinned to ensure code changes are reviewed
 edx-rest-api-client
 edx-search
 edx-submissions