super-linter: validate the Dockerfile with hadolint

https://github.com/super-linter/super-linter?tab=readme-ov-file#configure-super-linter

https://github.com/hadolint/hadolint

https://github.com/hadolint/hadolint?tab=readme-ov-file#configure

https://github.com/hadolint/hadolint/wiki/DL3042

.github/linters/.hadolint.yaml

@@ -0,0 +1,4 @@
+failure-threshold: info
+ignored:
+  - DL3008 # https://github.com/hadolint/hadolint/wiki/DL3008
+  - DL3013 # https://github.com/hadolint/hadolint/wiki/DL3013

.github/workflows/super-linter.yml

@@ -24,6 +24,7 @@ jobs:
         env:
           VALIDATE_BASH: true
           # VALIDATE_BASH_EXEC: true
+          VALIDATE_DOCKERFILE_HADOLINT: true
           # VALIDATE_EDITORCONFIG: true
           VALIDATE_GITLEAKS: true
           # VALIDATE_SHELL_SHFMT: true

Dockerfile

@@ -8,6 +8,6 @@ WORKDIR /app
 
 COPY Gemfile Gemfile.lock .pre-commit-config.yaml ./
 
-RUN bundle install && pip3 install pre-commit && git init . && pre-commit install-hooks
+RUN bundle install && pip3 install --no-cache-dir pre-commit && git init . && pre-commit install-hooks
 
 COPY . .