cargo: bump async-imap from c2e92df to bb73dfc

Bumps [async-imap](https://github.com/async-email/async-imap) from `c2e92df` to `bb73dfc`.
- [Release notes](https://github.com/async-email/async-imap/releases)
- [Commits](c2e92dfd33...bb73dfc203)

---
updated-dependencies:
- dependency-name: async-imap
  dependency-type: direct:production
...

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

Cargo.lock

@@ -212,7 +212,7 @@ dependencies = [
 [[package]]
 name = "async-imap"
 version = "0.5.0"
-source = "git+https://github.com/async-email/async-imap#c2e92dfd33b000c7f57612b41ca776b4d8784cc3"
+source = "git+https://github.com/async-email/async-imap#bb73dfc2034737cb0849d707edaa71e9ebd0faea"
 dependencies = [
  "async-native-tls",
  "async-std",
@@ -221,9 +221,9 @@ dependencies = [
  "chrono",
  "futures",
  "imap-proto",
- "lazy_static",
  "log",
  "nom 6.1.2",
+ "once_cell",
  "ouroboros",
  "pin-utils",
  "stop-token 0.2.0",