Update dependency composer/composer to v2.6.6

Signed-off-by: milkmaker <milkmaker@mailcow.de>

data/Dockerfiles/phpfpm/Dockerfile

@@ -12,7 +12,7 @@ ARG MEMCACHED_PECL_VERSION=3.2.0
 # renovate: datasource=github-tags depName=phpredis/phpredis versioning=semver-coerced extractVersion=(?<version>.*)$
 ARG REDIS_PECL_VERSION=6.0.1
 # renovate: datasource=github-tags depName=composer/composer versioning=semver-coerced extractVersion=(?<version>.*)$
-ARG COMPOSER_VERSION=2.6.5
+ARG COMPOSER_VERSION=2.6.6
 
 RUN apk add -U --no-cache autoconf \
   aspell-dev \