Bug 1826304 - Update base64 in some in-tree crates. r=glandium,webdriver-reviewers,necko-reviewers,supply-chain-reviewers,jesup,jgraham,emilio

Patch old base64 0.13 to 0.21 to avoid introducing the dup dependency.

Differential Revision: https://phabricator.services.mozilla.com/D175116