Fix Dockerfile build: add dev headers to .build-deps

- Added oniguruma-dev, libxml2-dev, libzip-dev to .build-deps
- These headers are required for compiling mbstring, xml, and zip extensions
- Headers are correctly removed after compilation via 'apk del .build-deps'
- Fixes: 'Package requirements (oniguruma) were not met' error

Dockerfile

@@ -35,7 +35,8 @@ WORKDIR /var/www
 # Install build dependencies first (will be removed later)
 RUN apk add --no-cache --virtual .build-deps \
     gcc g++ make autoconf libtool linux-headers \
-    libpng-dev libjpeg-turbo-dev freetype-dev
+    libpng-dev libjpeg-turbo-dev freetype-dev \
+    oniguruma-dev libxml2-dev libzip-dev
 
 # Install runtime dependencies
 RUN apk add --no-cache \