Dockerfile: refer to perl 5.38.x

...per complaints of earlier auto-build iterations after PR oetiker#624 merge

Signed-off-by: Jim Klimov <jimklimov@gmail.com>

Dockerfile

@@ -1,6 +1,6 @@
 
 ##### Builder image
-ARG PERL_BUILD_VERSION=5.30-buster
+ARG PERL_BUILD_VERSION=5.38-buster
 ARG ALPINE_VERSION=3.19
 FROM docker.io/library/perl:${PERL_BUILD_VERSION} as builder
 
@@ -17,7 +17,7 @@ RUN \
 ##### Runtime image
 FROM docker.io/library/alpine:${ALPINE_VERSION} as runtime
 
-ARG PERL_VERSION=5.30.3-r0
+ARG PERL_VERSION=5.38.2-r0
 
 RUN \
   # nano is for the interactive "edit" command in znapzendzetup if preferred over vi