Update base64 requirement from 0.13 to 0.21 (#608)

Updates the requirements on [base64](https://github.com/marshallpierce/rust-base64) to permit the latest version.
- [Release notes](https://github.com/marshallpierce/rust-base64/releases)
- [Changelog](https://github.com/marshallpierce/rust-base64/blob/master/RELEASE-NOTES.md)
- [Commits](marshallpierce/rust-base64@v0.13.0...v0.21.0)

---
updated-dependencies:
- dependency-name: base64
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Dominic <git@msrd0.de>

examples/websocket/Cargo.toml

@@ -13,4 +13,4 @@ tokio-tungstenite = "0.18"
 tokio = "1.11.0"
 pretty_env_logger = "0.4"
 sha1 = "0.10"
-base64 = "0.13"
+base64 = "0.21"

examples/websocket/src/ws.rs

@@ -1,3 +1,4 @@
+use base64::prelude::*;
 use gotham::hyper::header::{
     HeaderValue, CONNECTION, SEC_WEBSOCKET_ACCEPT, SEC_WEBSOCKET_KEY, UPGRADE,
 };
@@ -57,7 +58,7 @@ fn accept_key(key: &[u8]) -> String {
     let mut sha1 = Sha1::default();
     sha1.update(key);
     sha1.update(WS_GUID);
-    base64::encode(&sha1.finalize())
+    BASE64_STANDARD.encode(&sha1.finalize())
 }
 
 #[cfg(test)]

gotham/Cargo.toml

@@ -30,7 +30,7 @@ borrow-bag = { path = "../misc/borrow_bag", version = "1.1" }
 gotham_derive = { path = "../gotham_derive", version = "0.7", optional = true }
 
 anyhow = "1.0"
-base64 = "0.13"
+base64 = "0.21"
 bincode = { version = "1.0", optional = true }
 bytes = "1.0"
 cookie = "0.15"

gotham/src/middleware/session/mod.rs

@@ -8,6 +8,7 @@ use std::panic::RefUnwindSafe;
 use std::pin::Pin;
 use std::sync::{Arc, Mutex, PoisonError};
 
+use base64::prelude::*;
 use cookie::{Cookie, CookieJar};
 use futures_util::future::{self, FutureExt, TryFutureExt};
 use hyper::header::SET_COOKIE;
@@ -847,7 +848,7 @@ where
         };
 
         SessionIdentifier {
-            value: base64::encode_config(&bytes[..], base64::URL_SAFE_NO_PAD),
+            value: BASE64_URL_SAFE_NO_PAD.encode(&bytes[..]),
         }
     }
 }