ci: push image for all next branches

Currently the docker image is published for the next branch. If we have
two next branches (e.g. durng a pending OpenWrt release), a branch like
"next-24.10" would not be pushing a docker image.

Match the push action to all branches starting with next. This is
helpful if a downstream CI builds using the Gluon docker image.

Signed-off-by: David Bauer <[email protected]>

Author: blocktrron

.github/workflows/build-container.yml

@@ -5,7 +5,7 @@ on:
   push:
     branches:
       - 'main'
-      - 'next'
+      - 'next*'
       - 'v202[0-9].[0-9].x'
     tags:
       - 'v*'