Update to gosu 1.16

See https://github.com/tianon/gosu/releases/tag/1.16 (especially https://github.com/tianon/gosu/blob/master/SECURITY.md)

Author: tianon

5.7/Dockerfile.debian

@@ -7,7 +7,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends gnupg dirmngr &
 
 # add gosu for easy step-down from root
 # https://github.com/tianon/gosu/releases
-ENV GOSU_VERSION 1.14
+ENV GOSU_VERSION 1.16
 RUN set -eux; \
 	savedAptMark="$(apt-mark showmanual)"; \
 	apt-get update; \

5.7/Dockerfile.oracle

@@ -21,7 +21,7 @@ RUN set -eux; \
 
 # add gosu for easy step-down from root
 # https://github.com/tianon/gosu/releases
-ENV GOSU_VERSION 1.14
+ENV GOSU_VERSION 1.16
 RUN set -eux; \
 # TODO find a better userspace architecture detection method than querying the kernel
 	arch="$(uname -m)"; \