feat(postgres): support Homebrew for Apple Silicon (#10618)

plugins/postgres/postgres.plugin.zsh

@@ -1,8 +1,13 @@
 # Aliases to control Postgres
 # Paths noted below are for Postgres installed via Homebrew on OSX
+if (( ! $+commands[brew] )); then
+  return
+fi
 
-alias startpost='pg_ctl -D /usr/local/var/postgres -l /usr/local/var/postgres/server.log start'
-alias stoppost='pg_ctl -D /usr/local/var/postgres stop -s -m fast'
-alias restartpost='stoppost && sleep 1 && startpost'
-alias reloadpost='pg_ctl reload -D /usr/local/var/postgres -s'
-alias statuspost='pg_ctl status -D /usr/local/var/postgres -s'
+local PG_BREW_DIR=$(brew --prefix)/var/postgres
+
+alias startpost="pg_ctl -D $PG_BREW_DIR -l $PG_BREW_DIR/server.log start"
+alias stoppost="pg_ctl -D $PG_BREW_DIR stop -s -m fast"
+alias restartpost="stoppost && sleep 1 && startpost"
+alias reloadpost="pg_ctl reload -D $PG_BREW_DIR -s"
+alias statuspost="pg_ctl status -D $PG_BREW_DIR -s"