update prezto

.zprezto/modules/prompt/external/powerlevel9k/docker/zshing/Dockerfile

@@ -0,0 +1,7 @@
+ARG base
+FROM p9k:${base}
+
+COPY docker/zshing/install.zsh /tmp/
+RUN zsh /tmp/install.zsh
+
+COPY ./ p9k/

.zprezto/modules/prompt/external/powerlevel9k/docker/zshing/install.zsh

@@ -0,0 +1,16 @@
+#!zsh
+
+# install zshing https://github.com/zakariaGatter/zshing
+git clone https://github.com/zakariaGatter/zshing.git ~/.zshing/zshing
+
+# Link P9K in zshing directory
+ln -nsf ~/p9k ~/.zshing/powerlevel9k
+
+{
+  echo
+  echo 'ZSHING_PLUGINS=(
+     "bhilburn/powerlevel9k"
+ )'
+  echo
+  echo "source ~/.zshing/zshing/zshing.zsh"
+} >> ~/.zshrc