use pre-built image for portage-utils

.gitea/actions/drop-ebuilds-matching/Dockerfile

@@ -1,5 +0,0 @@
-FROM gentoo/portage:latest as portage
-FROM gentoo/stage3:amd64-openrc
-COPY --from=portage /var/db/repos/gentoo /var/db/repos/gentoo
-RUN emerge -q app-portage/portage-utils && rm -Rf /var/db/repos/gentoo
-ENTRYPOINT [ "/bin/bash" ]

.gitea/actions/drop-ebuilds-matching/action.yml

@@ -12,7 +12,8 @@ outputs:
     description: "space-separated list of removed ebuild versions"
 runs:
   using: docker
-  image: Dockerfile
+  image: docker://git.ratigorsk-12.ru/gentoo/pkgdev-docker:master
+  entrypoint: /bin/bash
   args:
     - -c
     - |