cocoapods.py generates some JSON-related URLs that lead to a 404

In connection with a `purl2url` [issue](https://github.com/package-url/packageurl-python/issues/143) in `packageurl-python`, I've been exploring the URL-related code in packagedcode's [cocoapods.py](https://github.com/nexB/scancode-toolkit/blob/develop/src/packagedcode/cocoapods.py). With the four PURL spec [examples for cocoapods](https://github.com/package-url/purl-spec/blob/master/PURL-TYPES.rst#cocoapods),

```
pkg:cocoapods/AFNetworking@4.0.1
pkg:cocoapods/MapsIndoors@3.24.0
pkg:cocoapods/ShareKit@2.0#Twitter
pkg:cocoapods/GoogleUtilities@7.5.2#NSData+zlib
```

I got the following results looking for potentially useful JSON files. Using the pattern

```
f'https://raw.githubusercontent.com/CocoaPods/Specs/blob/master/Specs/{hashed_path}/{name}/{version}/{name}.podspec.json'
```

from the `get_urls()` `api_data_url` [variable](https://github.com/nexB/scancode-toolkit/blob/develop/src/packagedcode/cocoapods.py#L462-L467), we get the following URLs, each of which leads to a `404: Not Found` page:

- https://raw.githubusercontent.com/CocoaPods/Specs/blob/master/Specs/a/7/5/AFNetworking/4.0.1/AFNetworking.podspec.json
- https://raw.githubusercontent.com/CocoaPods/Specs/blob/master/Specs/f/c/a/MapsIndoors/3.24.0/MapsIndoors.podspec.json
- https://raw.githubusercontent.com/CocoaPods/Specs/blob/master/Specs/3/b/7/ShareKit/2.0/ShareKit.podspec.json
- https://raw.githubusercontent.com/CocoaPods/Specs/blob/master/Specs/0/8/4/GoogleUtilities/7.5.2/GoogleUtilities.podspec.json

A few lines above that pattern in `get)url()` is a pattern for the `specs_json_cdn_url ` [variable](https://github.com/nexB/scancode-toolkit/blob/develop/src/packagedcode/cocoapods.py#L460)

```
f'https://cdn.cocoapods.org/Specs/{hashed_path}/{name}/{version}/{name}.podspec.json'
```

For the same four cocoapods PURLs, this pattern generates valid URLs to cdn.cocoapods.org JSON files:

- https://cdn.cocoapods.org/Specs/a/7/5/AFNetworking/4.0.1/AFNetworking.podspec.json
- https://cdn.cocoapods.org/Specs/f/c/a/MapsIndoors/3.24.0/MapsIndoors.podspec.json
- https://cdn.cocoapods.org/Specs/3/b/7/ShareKit/2.0/ShareKit.podspec.json
- https://cdn.cocoapods.org/Specs/0/8/4/GoogleUtilities/7.5.2/GoogleUtilities.podspec.json

BTW, some of the URL data in these four `.json` files is not (or no longer) valid, e.g., the "homepage" URL for ShareKit (http://getsharekit.com/) leads to what might be a Turkish-language page -- https://smartem.org/. (The "source"/"git" URL (https://github.com/ShareKit/ShareKit.git) is valid and reflects that the last commit was made in December 2017.)