Update composer Docker tag to v2.7.7 (#184)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Dockerfile

@@ -2,7 +2,7 @@ FROM php:8.4.0alpha4-alpine
 
 ENV COMPOSER_HOME="/tmp/composer"
 
-COPY --from=composer:2.6.5 /usr/bin/composer /usr/bin/composer
+COPY --from=composer:2.7.7 /usr/bin/composer /usr/bin/composer
 
 RUN set -x \
     && apk add --no-cache git \