try this variant

.gitea/workflows/container.yaml

@@ -0,0 +1,12 @@
+name: Build Multiarch Container Image
+on: [push]
+jobs:
+  call-reusable-workflow:
+    uses: container/multiarch-build-workflow/.gitea/workflows/build.yaml@main
+    with:
+      repository: ${{ gitea.repository }}
+      ref_name: ${{ gitea.ref_name }}
+      sha: ${{ gitea.sha }}
+      registry_url: ${{ secrets.REGISTRY_URL }}
+      registry_user: ${{ secrets.REGISTRY_USER }}
+      registry_pw: ${{ secrets.REGISTRY_PW }}

.gitlab-ci.yml

@@ -1,59 +0,0 @@
-variables:
-  CONTAINER_NAME: thallian/confd-env
-
-build:
-  stage: build
-  image:
-    name: gcr.io/kaniko-project/executor:debug
-    entrypoint: [""]
-  script:
-    - mkdir -p /kaniko/.docker
-    - echo "{\"auths\":{\"$CI_REGISTRY\":{\"auth\":\"$(printf "%s:%s" "$CI_REGISTRY_USER" "$CI_REGISTRY_PASSWORD" | base64 | tr -d '\n')\"}}}" > /kaniko/.docker/config.json
-    - >-
-      /kaniko/executor
-      --context "$CI_PROJECT_DIR"
-      --dockerfile "$CI_PROJECT_DIR/Dockerfile"
-      --destination "$CONTAINER_NAME:$CI_COMMIT_SHA"
-      --destination "$CONTAINER_NAME:$CI_COMMIT_REF_NAME"
-      --destination "$CONTAINER_NAME:latest"
-
-downstream-php8-fpm:
-  stage: .post
-  trigger: containers/php8-fpm
-downstream-php7-fpm:
-  stage: .post
-  trigger: containers/php7-fpm
-downstream-postgres:
-  stage: .post
-  trigger: containers/postgres
-downstream-murmur:
-  stage: .post
-  trigger: containers/murmur
-downstream-molly-brown:
-  stage: .post
-  trigger: containers/molly-brown
-downstream-user-access:
-  stage: .post
-  trigger: containers/user-access
-downstream-koreader-sync:
-  stage: .post
-  trigger: containers/koreader-sync
-downstream-wikijs:
-  stage: .post
-  trigger: containers/wikijs
-downstream-minecraft:
-  stage: .post
-  trigger: containers/minecraft
-downstream-matrix-synapse:
-  stage: .post
-  trigger: containers/matrix-synapse
-downstream-dovecot:
-  stage: .post
-  trigger: containers/dovecot
-downstream-rspamd:
-  stage: .post
-  trigger: containers/rspamd
-downstream-postfix:
-  stage: .post
-  trigger: containers/postfix
-

Containerfile

@@ -1,4 +1,4 @@
-FROM docker.io/golang:1.13.14-alpine AS builder
+FROM docker.io/golang:1.21-alpine3.19 AS builder
 
 RUN apk --no-cache add \
     git \
@@ -8,10 +8,10 @@ RUN mkdir -p $GOPATH/src/github.com/kelseyhightower
 RUN git clone https://github.com/kelseyhightower/confd.git $GOPATH/src/github.com/kelseyhightower/confd
 
 WORKDIR $GOPATH/src/github.com/kelseyhightower/confd
-RUN git checkout v0.16.0
+RUN git checkout 919444eb6cf721d198b2bb18581d0f0b3734d107
 RUN make
 
-FROM docker.io/thallian/alpine-s6:3.16
+FROM docker.io/thallian/alpine-s6:3.19-3.1.6.2
 
 COPY --from=builder /go/src/github.com/kelseyhightower/confd/bin/confd /bin/confd