Update base64
This updates base64 to the latest version.
base64's MSRV is now 1.57.0 whereas headers is currently at 1.51.0. Do you think we should bump that?
FYI, hyper MSRV is 1.56 : https://github.com/hyperium/hyper/blob/master/docs/MSRV.md
@davidpdrsn #127 has addressed this
@seanmonstar Now we're on base64 v0.21.7 while the latest version is v0.22.1. Is it desired to submit a patch for upgrading? If so, I can take care of it.
Sure, if you want to submit a new patch, that'd be fine (assuming MSRV is under 1.63).
Checking their github, MSRV appears to still be 1.48