Upgrade `Base64` dependency

Is it possible to upgrade the dependency `Base64` from the current `~0.2.0` to latest (`1.1.0`)?

I have verified that `Base64` is really only used once in `http-browserify` code and changing versions wouldn't break anything even though the semver indicates otherwise.

The root cause of my problems is that `Base64 v0.2.0` offers WTFPL which is not white listed in our org. So static code analysis tools flag it as a policy violation. `Base64 v 1.1.0` , on the other hand allows Apache 2.0 which is white listed in our org.

If there is a way to install the latest version of `Base64` and make `http-browserify` point to this latest version then that could work as well. Note that webpack aliasing won't work since we need to pass static code analysis scrutiny which probably works off `package-lock.json`

package-lock.json と http-browserify コード内の Base64 の単一の使用箇所を調査し、その依存関係がどのように宣言され、解決されるかを特定します。Base64 1.1.0 がその使用箇所を壊すことなく選択され、静的解析で WTFPL リリースではなく Apache 2.0 の依存関係として認識されれば完了です。

索引モデルが issue の本文から書いたものです。