fix: add COMPOSER_FLAGS to ignore platform reqs in builder

The FrankenPHP static builder's internal tooling requires extensions
that may not be available in the build container. Adding
--ignore-platform-reqs allows the build to proceed.

Author: joostfaassen

build/Dockerfile

@@ -35,7 +35,11 @@ ENV EMBED="/go/src/app/dist/app/"
 # Skip Caddy modules we don't need for CLI-only usage
 ENV XCADDY_ARGS=""
 
+# Ignore platform requirements for the builder's internal tooling
+ENV COMPOSER_FLAGS="--ignore-platform-reqs"
+
 # Build the static binary
 RUN EMBED="${EMBED}" \
     PHP_EXTENSIONS="${PHP_EXTENSIONS}" \
+    COMPOSER_FLAGS="${COMPOSER_FLAGS}" \
     ./build-static.sh