fix(jenkins): avoid Docker Hub frontend fetch in Dockerfile

Author: plexoos

Dockerfile

@@ -1,5 +1,3 @@
-# syntax=docker/dockerfile:latest
-
 ARG starenv=root5
 
 # Pick one from [gcc485, gcc11]
@@ -23,18 +21,16 @@ COPY . ${STAR}
 
 SHELL ["/bin/bash", "-l", "-c"]
 
-RUN <<EOF
-	set -e
-	[[ $compiler = "gcc485" ]] && EXTRA_CXXFLAGS="-Werror" || EXTRA_CXXFLAGS=""
-	cons EXTRA_CXXFLAGS="$EXTRA_CXXFLAGS"
-	find .$STAR_HOST_SYS -name *.o -exec rm '{}' \;
-EOF
+RUN set -e; \
+	if [ "$compiler" = "gcc485" ]; then EXTRA_CXXFLAGS="-Werror"; else EXTRA_CXXFLAGS=""; fi; \
+	cons EXTRA_CXXFLAGS="$EXTRA_CXXFLAGS"; \
+	find ".$STAR_HOST_SYS" -name '*.o' -exec rm '{}' \;
 
-COPY --chmod=0755 <<-"EOF" /opt/entrypoint.sh
-	#!/bin/bash -l
-	set -e
-	install $STAR/StRoot/macros/.rootrc .
-	exec "$@"
+RUN cat > /opt/entrypoint.sh <<'EOF' && chmod 0755 /opt/entrypoint.sh
+#!/bin/bash -l
+set -e
+install "$STAR/StRoot/macros/.rootrc" .
+exec "$@"
 EOF
 
 ENTRYPOINT ["/opt/entrypoint.sh"]