[revert] hijack the branch to point at to see if it works

Author: jason-famedly

.ci/scripts/checkout_complement.sh

@@ -21,5 +21,5 @@ for BRANCH_NAME in "$GITHUB_HEAD_REF" "$GITHUB_BASE_REF" "${GITHUB_REF#refs/head
     continue
   fi
 
-  (wget -O - "https://github.com/famedly/complement/archive/$BRANCH_NAME.tar.gz" | tar -xz --strip-components=1 -C complement) && break
+  (wget -O - "https://github.com/famedly/complement/archive/msc3911.tar.gz" | tar -xz --strip-components=1 -C complement) && break
 done