ci: Publish to Gitea

registry.pyrocufflink.blue is going away.  All container images hosted
there are being moved to Gitea.

ci/Jenkinsfile

@@ -53,10 +53,15 @@ pipeline {
         stage('Publish Container') {
             steps {
                 container('buildah') {
+                    withCredentials([usernameColonPassword(
+                        credentialsId: 'jenkins-packages',
+                        variable: 'BUILDAH_CREDS',
+                    )]) {
                         sh '. ci/publish-container.sh'
                     }
                 }
             }
+        }
 
     }
 }

ci/publish-container.sh

@@ -4,7 +4,9 @@
 
 push() {
     tag=$(tag_name "$1")
-    buildah push pythonctnr:$(tag_name ${BUILD_TAG}) registry.pyrocufflink.blue/pythonctnr:${tag}
+    buildah push --creds "${BUILDAH_CREDS}" \
+        pythonctnr:$(tag_name ${BUILD_TAG}) \
+        git.pyrocufflink.net/containerimages/pythonctnr:${tag}
 }
 
 push ${BUILD_TAG}