feat: Allow building pigeon files

src/flutter/build.sh

@@ -80,6 +80,12 @@ while [[ $# -gt 0 ]]; do
       SEND_NOTIFICATION=n
       shift
       ;;
+    --pigeon)
+      # Specifies to run `dart run pigeon --input $2`
+      PIGEON_FILES="$PIGEON_FILES $2"
+      shift
+      shift
+      ;;
     *)
       echo "Unknown argument: $1"
       shift
@@ -113,6 +119,7 @@ echo "===== ${NAME} ====="
 echo "Building version ${version}"
 echo "Moving APKs into ${release_dir} after build"
 echo "Clean build:               ${CLEAN_BUILD}"
+echo "Pigeons to build:         ${PIGEON_FILES}"
 echo "Skipping build:            ${SKIP_BUILD}"
 echo "Sending notification:      ${SEND_NOTIFICATION}"
 echo "APKs already signed:       ${ALREADY_SIGNED}"
@@ -155,6 +162,11 @@ else
   # Build everything again
   flutter pub run build_runner build --delete-conflicting-outputs
 
+  # Build pigeons
+  for pigeon in $PIGEON_FILES; do
+    dart run pigeon --input $pigeon
+  done
+
   # Build the release apk
   flutter build apk \
     --release \