Change the default container used

The container in this repository is based on the same one initially specified,
but contains some extra things needed for running and testing my configuration.

.gitlab-ci.yml

@@ -1,4 +1,4 @@
-image: silex/emacs:26.3-alpine-dev
+image: registry.gitlab.com/ryuslash/emacs-config
 
 stages:
   - pre-package-multifile
@@ -206,84 +206,72 @@ unit-test-oni-php:
 
 integration-test-oni-alert:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-alert TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-autohotkey:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-autohotkey TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-bat:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-bat TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-bats:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-bats TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-company:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-company TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-conf:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-conf TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-counsel:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-counsel TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-csharp:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-csharp TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-css:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-css TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-bookmark:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-bookmark TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-browse-url:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-browse-url TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-core:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   before_script:
@@ -292,84 +280,72 @@ integration-test-oni-core:
 
 integration-test-oni-cpp:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-cpp TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-docker:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-docker TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-fish:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-fish TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-gui:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-gui TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-haskell:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-haskell TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-ivy:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-ivy TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-json:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-json TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-org:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-org TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-paredit:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-paredit TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-prescient:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-prescient TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-scheme:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-scheme TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-yasnippet:
   stage: integration-test
-  image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
   script: make integration-test-oni-yasnippet TEST_ARCHIVE=$(realpath bin/)