fix: re-add entrypoint

It is broken but we still want something like this...

plugins/builder-railpack/dockerfiles/builder-build.Dockerfile

@@ -1,2 +1,7 @@
 ARG APP_IMAGE
 FROM $APP_IMAGE
+
+RUN printf '#!/usr/bin/env bash\nset -x\nexec bash -l -c -- \"$*\"\n' > /usr/local/bin/entrypoint && \
+    chmod +x /usr/local/bin/entrypoint
+
+ENTRYPOINT ["/usr/local/bin/entrypoint"]

plugins/builder-railpack/dockerfiles/entrypoint

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+
+echo "#!/usr/bin/env bash" > /tmp/cmd
+echo "" >> /tmp/cmd
+echo "$@" >> /tmp/cmd
+exec bash "$@"