Use this script when project has multi environments by Configurations.

setup_firebase_plist.sh

# Name of the resource to copy
INFO_PLIST_FILE=GoogleService-Info.plist

# Get references to debug and release versions of the plist file
DEV_INFO_PLIST_FILE=${PROJECT_DIR}/${TARGET_NAME}/Firebase/Development/${INFO_PLIST_FILE}
PROD_INFO_PLIST_FILE=${PROJECT_DIR}/${TARGET_NAME}/Firebase/Production/${INFO_PLIST_FILE}

# Make sure the debug version exists
echo "Looking for ${INFO_PLIST_FILE} in ${DEV_INFO_PLIST_FILE}"
if [ ! -f $DEV_INFO_PLIST_FILE ] ; then
    echo "File GoogleService-Info.plist (debug) not found."
    exit 1
fi

# Make sure the release version exists
echo "Looking for ${INFO_PLIST_FILE} in ${PROD_INFO_PLIST_FILE}"
if [ ! -f $PROD_INFO_PLIST_FILE ] ; then
    echo "File GoogleService-Info.plist (release) not found."
    exit 1
fi

# Get a reference to the destination location for the plist file
PLIST_DESTINATION=${BUILT_PRODUCTS_DIR}/${PRODUCT_NAME}.app/${INFO_PLIST_FILE}
echo "Copying ${INFO_PLIST_FILE} to final destination: ${PLIST_DESTINATION}"

# Copy the appropiate file to app bundle
if [ "${CONFIGURATION}" == "Debug (Development)" -o "${CONFIGURATION}" == "Release (Development)" ] ; then
    echo "File ${DEV_INFO_PLIST_FILE} copied"
    cp "${DEV_INFO_PLIST_FILE}" "${PLIST_DESTINATION}"
else
    echo "File ${PROD_INFO_PLIST_FILE} copied"
    cp "${PROD_INFO_PLIST_FILE}" "${PLIST_DESTINATION}"
fi