我已经创建了两个git仓库，我们需要使用PHP的composer将它们安装到我们的一个Web应用程序中。每个仓库有两个分支，分别为master和dev-master。
在我想要安装的项目中，我创建了以下composer.json包配置：

{
    "name": "laravel/laravel",
    "description": "The Laravel Framework.",
    "keywords": ["framework", "laravel"],
    "license": "proprietary",
    "repositories": [
        {
            "type": "package",
            "package": {
                "name": "impression-works/pdf-generator",
                "version": "dev-master",
                "source": {
                    "url": "git@github.com:...",
                    "type": "git",
                    "reference": "dev-master"
                }
            }
        },
        {
            "type": "package",
            "package": {
                "name": "impression-works/psd-templates",
                "version": "dev-master",
                "source": {
                    "url": "git@github.com:...",
                    "type": "git",
                    "reference": "dev-master"
                }
            }
        }
    ],
    "require": {
        // ...
        "impression-works/psd-templates": "dev-master",
        "impression-works/pdf-generator": "dev-master"
    },
    "autoload": {
        // ...
        "psr-0": {
            "ImpressionWorks\\PsdTemplates": "vendor/impression-works/psd-templates/src",
            "ImpressionWorks\\PdfGenerator": "vendor/impression-works/pdf-generator/src"
        }
    },
    // ...
    "config": {
        "preferred-install": "dist"
    },
    "minimum-stability": "stable"
}

当我最初运行composer update或composer install时，impression-works包安装得很好，但是，如果我对这些存储库进行更改，并将其推送到dev-master，则任何对composer update的连续调用都只是报告：

Nothing to install or update

我如何强制composer更新到我们这两个自定义包的最新提交？