fix(deps): update rust crate base64 to 0.22

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
base64	dependencies	minor	0.21 -> 0.22

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Release Notes

marshallpierce/rust-base64 (base64)

### [`v0.22.0`](https://togithub.com/marshallpierce/rust-base64/blob/HEAD/RELEASE-NOTES.md#0220) [Compare Source](https://togithub.com/marshallpierce/rust-base64/compare/v0.21.7...v0.22.0) - `DecodeSliceError::OutputSliceTooSmall` is now conservative rather than precise. That is, the error will only occur if the decoded output *cannot* fit, meaning that `Engine::decode_slice` can now be used with exactly-sized output slices. As part of this, `Engine::internal_decode` now returns `DecodeSliceError` instead of `DecodeError`, but that is not expected to affect any external callers. - `DecodeError::InvalidLength` now refers specifically to the *number of valid symbols* being invalid (i.e. `len % 4 == 1`), rather than just the number of input bytes. This avoids confusing scenarios when based on interpretation you could make a case for either `InvalidLength` or `InvalidByte` being appropriate. - Decoding is somewhat faster (5-10%)

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