Specify Dockerfile syntax version

shepmaster · shepmaster · commit d7c2c1faeeb1 · 2023-06-19T20:56:21.000-04:00
diff --git a/compiler/base/Dockerfile b/compiler/base/Dockerfile
@@ -1,3 +1,5 @@
+#syntax=docker/dockerfile:1.5
+
 FROM ubuntu:20.04 as toolchain
 
 ARG channel
