PackageReleaseProcedure.md

@@ -24,6 +24,10 @@
 1. Merge `debian/buster` into `debian/bullseye`.  There will be a merge conflict in the changelog.  You will need to accept the new changelog entry from debian/buster, but change the version from `+deb10` to `+deb11`.
 1. commit
 1. clean merge files with `git clean -f`
+1. Import from the master branch with
+    ```
+    gbp import-ref master -u <version> --upstream-tag='%(version)s' --debian-branch=debian/buster
+    ```
 1. Tag the debian branch with
    ```
    gbp tag --debian-branch=debian/buster