feat(half-life): add virtualenv prompt (#11708)

themes/half-life.zsh-theme

@@ -89,5 +89,9 @@ ZSH_THEME_RUBY_PROMPT_PREFIX="with%F{red} "
 ZSH_THEME_RUBY_PROMPT_SUFFIX="%{$reset_color%}"
 ZSH_THEME_RVM_PROMPT_OPTIONS="v g"
 
+# virtualenv prompt settings
+ZSH_THEME_VIRTUALENV_PREFIX=" with%F{red} "
+ZSH_THEME_VIRTUALENV_SUFFIX="%{$reset_color%}"
+
 setopt prompt_subst
-PROMPT="${purple}%n%{$reset_color%} in ${limegreen}%~%{$reset_color%}\$(ruby_prompt_info)\$vcs_info_msg_0_${orange} λ%{$reset_color%} "
+PROMPT="${purple}%n%{$reset_color%} in ${limegreen}%~%{$reset_color%}\$(virtualenv_prompt_info)\$(ruby_prompt_info)\$vcs_info_msg_0_${orange} λ%{$reset_color%} "