Alpine docker image: added subversion package for g.extension (#261)

docker/alpine/Dockerfile_alpine

@@ -80,6 +80,7 @@ ENV PACKAGES="\
       proj-util \
       sqlite \
       sqlite-libs \
+      subversion \
       tiff \
       zstd \
       zstd-libs \

docker/alpine/Dockerfile_alpine_wxgui

@@ -82,6 +82,7 @@ ENV PACKAGES="\
       proj-util \
       sqlite \
       sqlite-libs \
+      subversion \
       tiff \
       wxgtk-base \
       wxgtk \