Update Hugo to version 0.56.2

Dockerfile

@@ -9,9 +9,9 @@
 # to work around segmentation fault issues.
 FROM golang:1.12-alpine
 ARG HUGO=hugo
-ARG HUGO_VERSION=0.56.1
-ARG HUGO_SHA=a02bba8e9391008e4d773bbd09e9f11a35f00d599b668e388ae0857dbef48a54
-ARG HUGO_EXTENDED_SHA=af68761aaae76954cfd78a99b310143998efb629e47d2048f8e24b3311f23a28
+ARG HUGO_VERSION=0.56.2
+ARG HUGO_SHA=4b9abd6339ccd5b432c4872be82b9ee9030e1f6242e452e6fe47382808971826
+ARG HUGO_EXTENDED_SHA=853e4a81a97dfb0830e8db8225d19939da9b0c042220c39592cbadc770dda99c
 RUN set -eux && \
     case ${HUGO} in \
       *_extended) \