[workspace] Automate bazelisk_internal upgrades

[tyler-yankee]

Create an upgrade.py script which supplements the GitHub upgrade performed by new_release.py. That is, unlike e.g. crate_universe for which the upgrade script is the entire upgrade, here we wish to still perform the automated upgrade (fetch from GitHub), and then just use the script to sync some additional files.

This commit is only infrastructure (including a formatting-only change to packages.json); no actual upgrade is performed.

Towards #24850.

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This change is 

[tyler-yankee]

@tyler-yankee reviewed 6 files and all commit messages, and made 1 comment.
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tools/workspace/bazelisk_internal/upgrade.py line 49 at r1 (raw file):

            "bazel",
            ["bazel", "run", "//tools/workspace/bazelisk_internal:upgrade"],
        )

FYI This follows the pattern for drake/tools/workspace/crate_universe/upgrade.py established in #24810.

Code quote:

    bazelisk_license_path = os.environ.get("DRAKE_BAZELISK_LICENSE_PATH")
    if bazelisk_license_path is None:
        # Operate relative to the root of the Drake source tree.
        os.chdir(Path(__file__).resolve().parents[3])
        os.execvp(
            "bazel",
            ["bazel", "run", "//tools/workspace/bazelisk_internal:upgrade"],
        )

[tyler-yankee]

+a:@tom-osika for feature review, please.

@tyler-yankee made 1 comment.
Reviewable status: LGTM missing from assignee tom-osika, needs platform reviewer assigned, needs at least two assigned reviewers (waiting on tom-osika).