ci: build containers using buildah

.drone.yml

@@ -23,15 +23,18 @@ steps:
       event:
         exclude: [cron]
 
-  - name: kaniko-build
+  - name: buildah 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}
+    image: docker.io/library/alpine:3.16.2
+    environment:
+      BUILD_DATE: $(date -u +"%Y-%m-%dT%H:%M:%SZ")
+      VCS_REF: ${DRONE_COMMIT_SHA:0:7}
+      BUILDAH_ISOLATION: chroot
+      _BUILDAH_STARTED_IN_USERNS: ""
+    commands:
+      - apk update
+      - apk add --no-cache buildah
+      - buildah bud -f Containerfile --build-arg BUILD_DATE="$BUILD_DATE" --build-arg VCS_REF="$VCS_REF"
     when:
       ref:
         - refs/heads/feature-**
@@ -69,6 +72,6 @@ trigger:
 
 ---
 kind: signature
-hmac: 33bd2009f89e9c372006ab525b08184491c5c6ccc8941eeb11848eda0abd6ac6
+hmac: f2f21e0af4b1f6eb8c1e42ccd55d679009480b0a2c883185078dcfa5e158fb98
 
 ...