docker: T7170: fix sed pattern for change in OPAM install.sh

Author: dd010101

docker/Dockerfile

@@ -141,7 +141,7 @@ RUN dpkg-reconfigure ca-certificates; \
 # Installing OCAML needed to compile libvyosconfig
 RUN curl https://raw.githubusercontent.com/ocaml/opam/master/shell/install.sh \
       --output /tmp/opam_install.sh --retry 10 --retry-delay 5 && \
-    sed -i 's/read -r BINDIR/BINDIR=""/' /tmp/opam_install.sh && sh /tmp/opam_install.sh && \
+    sed -i 's/read_tty BINDIR/BINDIR=""/' /tmp/opam_install.sh && sh /tmp/opam_install.sh && \
     opam init --root=/opt/opam --comp=4.12.0 --disable-sandboxing
 
 RUN eval $(opam env --root=/opt/opam --set-root) && \