Update Hugo to version 0.76.4

Dockerfile

@@ -9,9 +9,9 @@
 # to work around segmentation fault issues.
 FROM golang:1.13-alpine
 ARG HUGO=hugo
-ARG HUGO_VERSION=0.76.3
-ARG HUGO_SHA=11a4262fca26e8edfb9d42b6e138e6907ea082dc5c7b8ecf26c65bbb63cae170
-ARG HUGO_EXTENDED_SHA=bea94d166e28adfc8377cba3d305a69c32bff4091426dc3eff9e3e2850113643
+ARG HUGO_VERSION=0.76.4
+ARG HUGO_SHA=723d36ad66082d1beef80a750277aff58de71eaae2d0fca7df6de737eec64e26
+ARG HUGO_EXTENDED_SHA=1257431bf06b0ad9614772d0d43c4b550987c5346860537551f1507c408e09e1
 RUN set -eux && \
     case ${HUGO} in \
       *_extended) \