CI: fix external pull requests

Using github.repository does not
work for third-party pull requests.

Author: pjonsson

.github/workflows/main.yml

@@ -18,6 +18,9 @@ on:
     types:
       - completed
 
+env:
+  DOCKER_IMAGE: ghcr.io/opendatacube/odc-stats
+
 permissions:
   contents: read
   packages: read
@@ -67,7 +70,7 @@ jobs:
   test-wheels:
     runs-on: ubuntu-latest
     container:
-      image: ghcr.io/${{ github.repository }}:latest
+      image: ${{ env.DOCKER_IMAGE }}:latest
       credentials:
         username: ${{ github.actor }}
         password: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/statistician-image.yml

@@ -20,6 +20,8 @@ on:
     types:
       - completed
 
+env:
+  DOCKER_IMAGE: ghcr.io/opendatacube/odc-stats
 
 permissions:
   id-token: write   # This is required for requesting the JWT
@@ -110,6 +112,6 @@ jobs:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
-          image_name: ${{ github.repository }}
+          image_name: ${{ env.DOCKER_IMAGE }}
           image_tag: latest,${{ needs.set_tags.outputs.image_tag }}
           build_extra_args: '{"--build-arg": "UPDATE_VERSION=${{ needs.set_tags.outputs.image_tag }}"}'