Package index: fix checksum and add URL support to parser
This MR has 3 commits to improve the index parser. A summary of the commits:
-
Improves the TestSinglePackage test to cover all supported tokens in the APK database.
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Fix two bugs that prevented the correct parsing of checksums in the package index:
- A bug that prevented catching the checksum entry
- A bug in the decoding algorithm that prevented the base64 to be read properly
- Add URL support to package and index parser
Signed-off-by: Adolfo García Veytia (Puerco) puerco@chainguard.dev