ci: add .drone.yml

hadolint: override severity of a warning

.drone.yml

@@ -0,0 +1,68 @@
+---
+kind: pipeline
+type: docker
+name: testing
+
+platform:
+  os: linux
+  arch: amd64
+
+steps:
+  - name: hadolint
+    pull: always
+    image: ghcr.io/hadolint/hadolint:v2.12.0-alpine
+    commands:
+      - hadolint --version
+      - hadolint Containerfile
+    when:
+      ref:
+        - refs/heads/development
+        - refs/heads/feature-**
+        - refs/pull/**
+        - refs/tags/**
+      event:
+        exclude: [cron]
+
+  - name: kaniko-build
+    pull: always
+    image: docker.io/immawanderer/drone-kaniko:linux-amd64
+    settings:
+      dockerfile: Containerfile
+      context: .
+      args:
+        - BUILD_DATE="$(date -u +"%Y-%m-%dT%H:%M:%SZ")"
+        - VCS_REF=${DRONE_COMMIT_SHA:0:7}
+    when:
+      ref:
+        - refs/heads/feature-**
+        - refs/pull/**
+        - refs/tags/**
+      event:
+        exclude: [cron]
+
+  - name: kaniko-publish
+    pull: always
+    image: docker.io/immawanderer/drone-kaniko:linux-amd64
+    settings:
+      dockerfile: Containerfile
+      context: .
+      args:
+        - BUILD_DATE="$(date -u +"%Y-%m-%dT%H:%M:%SZ")"
+        - VCS_REF=${DRONE_COMMIT_SHA:0:7}
+      tags:
+        - latest
+        - linux-amd64
+        - ${DRONE_COMMIT_SHA:0:8}
+      repo: immawanderer/${DRONE_REPO_NAME}
+      username: immawanderer
+      password:
+        from_secret: dh_token
+    when:
+      ref:
+        - refs/heads/development
+      event:
+        exclude: [pull_request, tag]
+
+trigger:
+  event: [push, pull_request, cron, tag]
+...

.hadolint.yaml

@@ -1,2 +1,9 @@
 ---
 ignored:
+
+failure-threshold: warning
+
+override:
+  info:
+    # DL3018 warning: Pin versions in apk add. Instead of `apk add <package>` use `apk add <package>=<version>`
+    - DL3018

.pre-commit-config.yaml

@@ -5,6 +5,8 @@ repos:
     rev: v4.2.0
     hooks:
       - id: check-merge-conflict
+      - id: check-yaml
+        exclude: .drone.yml
   - repo: https://git.dotya.ml/wanderer/hadolint-pre-commit
     rev: v0.0.1
     hooks: