Fix shell inside RUN directive

Earthfile

@@ -279,7 +279,7 @@ base-image:
  ELSE
  RUN apt install -y apt-transport-https ca-certificates curl && \
  echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list' && \
- curl -fsSL -o postgresql.asc https://www.postgresql.org/media/keys/ACCC4CF8.asc
+ curl -fsSL -o postgresql.asc https://www.postgresql.org/media/keys/ACCC4CF8.asc && \
  gpg --batch --yes --dearmor -o /etc/apt/trusted.gpg.d/postgresql.gpg postgresql.asc && \
  rm postgresql.asc && \
  apt update && \