.gitlab-ci.yml: switch to alpine:latest, manually specify packages

.gitlab-ci.yml

@@ -1,4 +1,4 @@
-image: python:alpine
+image: alpine:latest
 
 variables:
   JEKYLL_ENV: production
@@ -11,7 +11,7 @@ cache:
     - ${CI_PROJECT_DIR}/bundle
 
 before_script:
-  - apk install --no-cache ruby-bundler
+  - apk install --no-cache ruby ruby-bundler
   - bundle install
 
 test:
@@ -37,7 +37,7 @@ pages:
 gitlab-ci-pre-commit:
   stage: build
   before_script:
-    - apk add --no-cache git gcc musl-dev bash
+    - apk add --no-cache python3 py3-pip git gcc musl-dev bash
     - pip install pre-commit
   script:
     - pre-commit run --all-files --show-diff-on-failure