[PATCH for-4.19 2/4] CI: Adjust the usage of inline files

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

As per:

  
https://github.com/moby/buildkit/blob/master/frontend/dockerfile/docs/reference.md#here-documents

For inline files, use COPY with a heredoc, rather than opencoding it through
/bin/sh.

No practical change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Anthony PERARD <anthony.perard@xxxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Doug Goldstein <cardoe@xxxxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 automation/build/debian/jessie-i386.dockerfile  | 2 +-
 automation/build/debian/jessie.dockerfile       | 2 +-
 automation/build/debian/stretch-i386.dockerfile | 2 +-
 automation/build/debian/stretch.dockerfile      | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/automation/build/debian/jessie-i386.dockerfile 
b/automation/build/debian/jessie-i386.dockerfile
index f6eaa94ee523..1eb7ff11c7d3 100644
--- a/automation/build/debian/jessie-i386.dockerfile
+++ b/automation/build/debian/jessie-i386.dockerfile
@@ -12,7 +12,7 @@ WORKDIR /build
 ENTRYPOINT ["linux32"]
 
 # replace repos in archive as release is EOL
-RUN cat <<"END" > /etc/apt/sources.list
+COPY <<"END" /etc/apt/sources.list
 deb http://archive.debian.org/debian/ jessie main contrib non-free
 deb http://archive.debian.org/debian/ jessie-backports main contrib non-free
 deb http://archive.debian.org/debian-security/ jessie/updates main contrib 
non-free
diff --git a/automation/build/debian/jessie.dockerfile 
b/automation/build/debian/jessie.dockerfile
index a870e743fcaf..4c0ffe66f8fe 100644
--- a/automation/build/debian/jessie.dockerfile
+++ b/automation/build/debian/jessie.dockerfile
@@ -10,7 +10,7 @@ RUN mkdir /build
 WORKDIR /build
 
 # replace repos in archive as release is EOL
-RUN cat <<"END" > /etc/apt/sources.list
+COPY <<"END" /etc/apt/sources.list
 deb http://archive.debian.org/debian/ jessie main contrib non-free
 deb http://archive.debian.org/debian/ jessie-backports main contrib non-free
 deb http://archive.debian.org/debian-security/ jessie/updates main contrib 
non-free
diff --git a/automation/build/debian/stretch-i386.dockerfile 
b/automation/build/debian/stretch-i386.dockerfile
index ad8db692aaf2..8ec9c3a24667 100644
--- a/automation/build/debian/stretch-i386.dockerfile
+++ b/automation/build/debian/stretch-i386.dockerfile
@@ -12,7 +12,7 @@ WORKDIR /build
 ENTRYPOINT ["linux32"]
 
 # replace repos in archive as release is EOL
-RUN cat <<"END" > /etc/apt/sources.list
+COPY <<"END" /etc/apt/sources.list
 deb http://archive.debian.org/debian/ stretch main contrib non-free
 deb http://archive.debian.org/debian/ stretch-backports main contrib non-free
 deb http://archive.debian.org/debian-security/ stretch/updates main contrib 
non-free
diff --git a/automation/build/debian/stretch.dockerfile 
b/automation/build/debian/stretch.dockerfile
index 4dfd40b54277..2db4552662de 100644
--- a/automation/build/debian/stretch.dockerfile
+++ b/automation/build/debian/stretch.dockerfile
@@ -10,7 +10,7 @@ RUN mkdir /build
 WORKDIR /build
 
 # replace repos in archive as release is EOL
-RUN cat <<"END" > /etc/apt/sources.list
+COPY <<"END" /etc/apt/sources.list
 deb http://archive.debian.org/debian/ stretch main contrib non-free
 deb http://archive.debian.org/debian/ stretch-backports main contrib non-free
 deb http://archive.debian.org/debian-security/ stretch/updates main contrib 
non-free
-- 
2.39.2