Rust Members files are not detected properly

### Description

Rust Workspace member files are not detected properly, eg https://github.com/iron/iron
In a codebase having this tree structure
```shell
.
├── CONTRIBUTING.md
├── Cargo.toml
├── LICENSE
├── README.md
├── iron
│   ├── Cargo.toml
│   └── src
├── logger
│   ├── CONTRIBUTING.md
│   ├── Cargo.toml
│   ├── LICENSE
│   ├── README.md
│   ├── examples
│   └── src
├── mount
│   ├── Cargo.toml
│   ├── README.md
│   ├── examples
│   └── src
├── persistent
│   ├── Cargo.toml
│   ├── README.md
│   ├── examples
│   └── src
└── router
├── Cargo.toml
├── README.md
├── examples
└── src
```
The files like LICENSE inside the `logger` member is not detected properly as it has no `for_package` attribute associated with it
```json
{
"path": "iron-master.zip-extract/iron-master/logger/LICENSE",
"type": "file",
"name": "LICENSE",
"base_name": "LICENSE",
"extension": "",
"size": 1070,
"date": "2021-03-12",
"sha1": "7d3c0b5b44cba5c71e617e8da93529bc7cdc97b1",
"md5": "d0e069410387ade12a0e004a9390b370",
"sha256": "1d9c2bd0d5ac90f0265225209f0c29ee12611effbb6015fec6e98c4adc53fa0e",
"mime_type": "text/plain",
"file_type": "ASCII text",
"programming_language": null,
"is_binary": false,
"is_text": true,
"is_archive": false,
"is_media": false,
"is_source": false,
"is_script": false,
"package_data": [],
"for_packages": [],
"is_legal": true,
"is_manifest": false,
"is_readme": false,
"is_top_level": false,
"is_key_file": false,
"detected_license_expression": "mit",
"detected_license_expression_spdx": "MIT",
"license_detections": [
{
"license_expression": "mit",
"license_expression_spdx": "MIT",
"matches": [
{
"license_expression": "mit",
"spdx_license_expression": "MIT",
"from_file": "iron-master.zip-extract/iron-master/logger/LICENSE",
"start_line": 1,
"end_line": 1,
"matcher": "2-aho",
"score": 100.0,
"matched_length": 4,
"match_coverage": 100.0,
"rule_relevance": 100,
"rule_identifier": "mit_26.RULE",
"rule_url": "https://github.com/nexB/scancode-toolkit/tree/develop/src/licensedcode/data/rules/mit_26.RULE"
},
{
"license_expression": "mit",
"spdx_license_expression": "MIT",
"from_file": "iron-master.zip-extract/iron-master/logger/LICENSE",
"start_line": 5,
"end_line": 21,
"matcher": "2-aho",
"score": 100.0,
"matched_length": 161,
"match_coverage": 100.0,
"rule_relevance": 100,
"rule_identifier": "mit.LICENSE",
"rule_url": "https://github.com/nexB/scancode-toolkit/tree/develop/src/licensedcode/data/licenses/mit.LICENSE"
}
],
"identifier": "mit-86fcf017-3572-9813-b7e8-0a10ec4a120f"
}
],
"license_clues": [],
"percentage_of_license_text": 97.63,
"copyrights": [
{
"copyright": "Copyright (c) 2014 iron",
"start_line": 3,
"end_line": 3
}
],
"holders": [
{
"holder": "iron",
"start_line": 3,
"end_line": 3
}
],
"authors": [],
"emails": [],
"urls": [],
"files_count": 0,
"dirs_count": 0,
"size_count": 0,
"scan_errors": []
},
```
and hence create issue in creating `package_summary`