Update CI Docker file & add push hook

.github/workflows/Dockerfile → .github/ci-docker/Dockerfile

@@ -46,7 +46,7 @@ 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"; do \
+    && for VIPS_VERSION in "8.13" "8.14" "8.15"; 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 $VIPS_VERSION" \
@@ -59,7 +59,6 @@ RUN \
         --prefix=/root/vips/$VIPS_VERSION \
         --libdir=lib \
         -Dgtk_doc=false \
-        -Dintrospection=false \
       && ninja -C _build \
       && ninja -C _build install \
       && cd .. \

.github/ci-docker/hooks/push

@@ -0,0 +1,4 @@
+#!/bin/bash
+DATETAG=$(date +%Y%m%d%H%M)
+docker tag $IMAGE_NAME $DOCKER_REPO:$DATETAG
+docker push $DOCKER_REPO:$DATETAG