cargo: bump base64 from 0.13.1 to 0.20.0

Bumps [base64](https://github.com/marshallpierce/rust-base64) from 0.13.1 to 0.20.0.
- [Release notes](https://github.com/marshallpierce/rust-base64/releases)
- [Changelog](https://github.com/marshallpierce/rust-base64/blob/master/RELEASE-NOTES.md)
- [Commits](https://github.com/marshallpierce/rust-base64/compare/v0.13.1...v0.20.0)

---
updated-dependencies:
- dependency-name: base64
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.lock

@@ -371,6 +371,12 @@ version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9e1b586273c5702936fe7b7d6896644d8be71e6314cfe09d3167c95f712589e8"
 
+[[package]]
+name = "base64"
+version = "0.20.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ea22880d78093b0cbe17c89f64a7d457941e65759157ec6cb31a31d652b05e5"
+
 [[package]]
 name = "base64ct"
 version = "1.5.1"
@@ -877,7 +883,7 @@ dependencies = [
  "async-smtp",
  "async_zip",
  "backtrace",
- "base64 0.13.1",
+ "base64 0.20.0",
  "bitflags",
  "chrono",
  "criterion",

Cargo.toml

@@ -30,7 +30,7 @@ trust-dns-resolver = "0.22"
 tokio = { version = "1", features = ["fs", "rt-multi-thread", "macros"] }
 tokio-tar = { version = "0.3" } # TODO: integrate tokio into async-tar
 backtrace = "0.3"
-base64 = "0.13"
+base64 = "0.20"
 bitflags = "1.3"
 chrono = { version = "0.4", default-features=false, features = ["clock", "std"] }
 dirs = { version = "4", optional=true }