ROX-33230: Handle trailing slash in amzn2 updater

[BradLugo]

Description

https://cdn.amazonlinux.com/2/core/latest/x86_64/mirror.list currently returns a URL with a trailing slash, e.g., https://cdn.amazonlinux.com/2/core/2.0/x86_64/5c6fef27354d4abb2fae03725436346c134b4d9683f8f64279a2b307ef2b13dc/, which the updater will use and append /repodata/repomd.xml. However, https://cdn.amazonlinux.com/2/core/2.0/x86_64/5c6fef27354d4abb2fae03725436346c134b4d9683f8f64279a2b307ef2b13dc//repodata/repomd.xml will return a 403, whereas https://cdn.amazonlinux.com/2/core/2.0/x86_64/5c6fef27354d4abb2fae03725436346c134b4d9683f8f64279a2b307ef2b13dc/repodata/repomd.xml returns the correct data.

These changes use the stdlib url parsing and url methods to construct urls in a critical code path.

[github-actions]

/retest scanner-db-slim-on-push

[openshift-ci]

@github-actions[bot]: The /retest command does not accept any targets.
The following commands are available to trigger optional jobs:

/test e2e-tests

/test slim-e2e-tests

Use /test all to run all jobs.

Details

In response to this:

/retest scanner-db-slim-on-push

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[openshift-ci]

@BradLugo: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/e2e-tests	8b265a6	link	false	/test e2e-tests
ci/prow/slim-e2e-tests	8b265a6	link	false	/test slim-e2e-tests

Full PR test history. Your PR dashboard.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.