Update Hugo to version 0.78.0

Dockerfile

@@ -9,9 +9,9 @@
 # to work around segmentation fault issues.
 FROM golang:1.13-alpine
 ARG HUGO=hugo
-ARG HUGO_VERSION=0.77.0
-ARG HUGO_SHA=943779931c97fcb5aef58e44d0e65f417131914fa093dde3bc9da737ee1a7976
-ARG HUGO_EXTENDED_SHA=68de5318dd0beb9517b42233246bb8ef8f28b9fd7d2937db2d1c5c5605b3237b
+ARG HUGO_VERSION=0.78.0
+ARG HUGO_SHA=72964765fba61950d4ebb0d131f2cb585f26cddb4ee189e65d874263d2b70839
+ARG HUGO_EXTENDED_SHA=2c3d888439765d10d0713a197681c4ecd06c1aa14367d8f4eb3ad69f64c9714b
 RUN set -eux && \
     case ${HUGO} in \
       *_extended) \