Use Keitaro Ubuntu image for tests

As pytorch doesn't work on Alpine

#4

.github/workflows/test.yml

@@ -4,10 +4,9 @@ jobs:
   test:
     runs-on: ubuntu-latest
     container:
-      # The CKAN version tag of the Solr and Postgres containers should match
-      # the one of the container the tests run on.
-      # You can switch this base image with a custom image tailored to your project
-      image: ckan/ckan-dev:2.10
+      # Use the Keitaro Ubuntu-based image as pytorch doesn't work on alpine
+      # See amercader/ckanext-embeddings#4
+      image: keitaro/ckan:2.10.4-focal
     services:
       solr:
         image: ckan/ckan-solr:2.10-solr9-vector