build: add dart cache

.repo/build

@@ -30,16 +30,24 @@ for package in "${PACKAGES[@]}"; do
     # capture output for parsing dependencies
     makepkg_output=$(makepkg --printsrcinfo)
 
-    # cache downloaded crates
+    #
+    # cache various downloads
+    #
+    # rust - crates
     if grep -q "depends = rust\|cargo" <<<"$makepkg_output"; then
       EXTRA_ARGS+=(--bind-rw /var/cache/cargo:/build/.cargo)
     fi
 
-    # cache downloaded modules
+    # go - modules
     if grep -q "depends = go" <<<"$makepkg_output"; then
       EXTRA_ARGS+=(--bind-rw /var/cache/golang:/build/go)
     fi
 
+    # dart - packages
+    if grep -q "depends = dart" <<<"$makepkg_output"; then
+      EXTRA_ARGS+=(--bind-rw /var/cache/dartlang:/build/.pub-cache)
+    fi
+
     # build signed package in chroot & add to local repo
     aur build \
       --chroot \