gitlab-ci: upload built packages as artifacts

gitlab allows us to define artifacts that will be uploaded to gitlab and
available to download for some time.

Specify that the built packages should be uploaded to gitlab, along with
the public key.

.gitlab-ci.yml

@@ -25,11 +25,21 @@ lint:
   image: alpinelinux/alpine-gitlab-ci:latest
   script:
     - build.sh
+    - cp -ar ~/packages packages/
+    - mkdir -p keys
+    - cp ~/.abuild/*.rsa.pub keys/
+  artifacts:
+    paths:
+      - packages/
+      - keys/
+    expire_in: 1 day
   only:
     - merge_requests
 
 build-x86_64:
   extends: .build
+  artifacts:
+    name: MR${CI_MERGE_REQUEST_ID}_x86_64
   tags:
     - docker-alpine
     - ci-build
@@ -40,6 +50,8 @@ build-x86:
   image:
     name: alpinelinux/alpine-gitlab-ci:latest-x86
     entrypoint: ["linux32", "sh", "-c"]
+  artifacts:
+    name: MR${CI_MERGE_REQUEST_ID}_x86
   tags:
     - docker-alpine
     - ci-build
@@ -47,6 +59,8 @@ build-x86:
 
 build-s390x:
   extends: .build
+  artifacts:
+    name: MR${CI_MERGE_REQUEST_ID}_s390x
   tags:
     - docker-alpine
     - ci-build
@@ -54,6 +68,8 @@ build-s390x:
 
 build-ppc64le:
   extends: .build
+  artifacts:
+    name: MR${CI_MERGE_REQUEST_ID}_ppc64le
   tags:
     - docker-alpine
     - ci-build