Add build-ci-docker GH Actions workflow

.github/ci-docker/Dockerfile

@@ -1,4 +1,6 @@
-FROM ubuntu:noble
+FROM public.ecr.aws/ubuntu/ubuntu:noble
+
+ARG VIPS_VERSIONS="8.14 8.15 8.16"
 
 RUN apt-get -qq update \
   && apt-get install -y --no-install-recommends \
@@ -40,7 +42,7 @@ RUN \
   mkdir /root/vips \
     && cd /root/vips \
     && curl -s -S -L -o vips_releases.json "https://api.github.com/repos/libvips/libvips/releases" \
-    && for VIPS_VERSION in "8.13" "8.14" "8.15"; do \
+    && for VIPS_VERSION in $VIPS_VERSIONS; do \
       mkdir $VIPS_VERSION \
       && export VIPS_RELEASE=$(grep -m 1 "\"tag_name\": \"v$VIPS_VERSION." vips_releases.json | sed -E 's/.*"v([^"]+)".*/\1/') \
       && echo "Building Vips $VIPS_RELEASE as $VIPS_VERSION" \

.github/workflows/build-ci-docker.yml

@@ -0,0 +1,44 @@
+name: Build CI Docker
+
+on:
+  workflow_dispatch:
+    inputs:
+      vips_versions:
+        description: 'Whitespace separated list of libvips versions to build'
+        required: true
+        default: "8.14 8.15 8.16"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Generate Docker tag
+        id: tag
+        run: echo "tag=ghcr.io/imgproxy/imgproxy-ci:$(date +%Y%m%d%H%M)" >> "$GITHUB_OUTPUT"
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          file: ./.github/ci-docker/Dockerfile
+          tags: ${{ steps.tag.outputs.tag }}
+          platforms: linux/amd64
+          build-args: |
+            "VIPS_VERSIONS=${{ github.event.inputs.vips_versions }}"
+          push: true