Update base64 to 0.21

[Ayush1325]

Also added once_cell for caching the new Engine based APIs of base64

Signed-off-by: Ayush Singh ayushsingh1325@gmail.com

[Ayush1325]

Possibly a duplicate of #123 although the versions are different.

[seanmonstar]

Ah, I guess base64 decided to use the 2021 edition, requiring a newer compiler. Sigh. What version is needed?

[Ayush1325]

Ah, I guess base64 decided to use the 2021 edition, requiring a newer compiler. Sigh. What version is needed?

I think it's 1.57.0. Should I update this PR or would you like to do that separately?

[nicoxxl]

Beware, hyper MSRV is 1.56 : https://github.com/hyperium/hyper/blob/master/docs/MSRV.md

But 1.57.0 was released a little more than one year ago : https://blog.rust-lang.org/2021/12/02/Rust-1.57.0.html

[serprex]

@Ayush1325 please go ahead & update minrust in .github/workflows/ci.yml

[serprex]

@seanmonstar tungstenite opted to switch from base64 crate to data-encoding given how extensive latest changes are: https://github.com/snapview/tungstenite-rs/commit/c6769e3daebc064f1e1e711f552c7970a42d8346

would you prefer a PR replacing base64 with data-encoding?

[serprex]

Looks like base64 went ahead & bumped MSRV to 1.60 with 0.21.1: https://github.com/marshallpierce/rust-base64/pull/238

Created #139 as alternative to this PR

[Colerar]

Note: base64 released 0.21.3, and MSRV roll-backed to 1.48.

https://github.com/marshallpierce/rust-base64/blob/master/RELEASE-NOTES.md#0213

[serprex]

@seanmonstar with MSRV issues seeming to be resolved for base64, can this PR progress?

[seanmonstar]

Yea absolutely, let's do it :)

[seanmonstar]

Huh, well looks like with httpdate, we need an MSRV of 1.56 anyways. 🤷

[serprex]

Created #147 as that msrv change would be unrelated to this PR