Allow artifact promote jobs a little more control over renaming

In Zuul, we're publishing both the sdist and the js-content tarball,
but because of the strict naming rules encoded in the promote job,
they are both renamed to "zuul-master.tar.gz".  Instead, let the
js content job specify that it should have a slightly different
name.

Change-Id: I57e6173e3ee058665e908aba786f8966a8d812f4

playbooks/artifacts/promote.yaml

@@ -1,7 +1,8 @@
 - hosts: localhost
   vars:
     name_replacement: '.*?(-py.*?\.whl|\.tar\.gz)'
-    name_target: "{{zuul.project.short_name}}-{{zuul.branch | replace('/', '-')}}\\1"
+    name_extra: "{{ (artifact_extra_name|default('') and '-'+artifact_extra_name or '') | regex_replace('[^a-zA-z1-9_\\-.]', '') }}"
+    name_target: "{{zuul.project.short_name}}{{ name_extra }}-{{zuul.branch | replace('/', '-')}}\\1"
   tasks:
     - name: Check execution context
       when: "zuul.branch is not defined"

zuul.yaml

@@ -466,9 +466,14 @@
          The name of the job which built the artifacts which this
          job should download and promote.
 
-       .. zuul:jobvar:: download_artifact_name
+      .. zuul:jobvar:: download_artifact_name
 
          The name of the artifact.
+
+      .. zuul:jobvar:: artifact_extra_name
+
+         The artifact will be renamed to PROJECT-BRANCH.ext; if this
+         argument is present, it will be PROJECT-EXTRA-BRANCH.ext.
     abstract: True
     run: playbooks/artifacts/promote.yaml
     nodeset:
@@ -503,6 +508,7 @@
     vars:
       download_artifact_job: build-javascript-content-tarball
       download_artifact_name: javascript_content
+      artifact_extra_name: js-content
     secrets:
       - secret: opendev-zuul-tarballs
         name: afs