tokio-imap: bump MSRV to 1.70 (for tokio 1.39)

Author: djc

.github/workflows/main.yml

@@ -52,7 +52,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: 1.67.0
+          toolchain: 1.70.0
       - run: cargo check --manifest-path tokio-imap/Cargo.toml --lib --all-features
 
   coverage:

tokio-imap/Cargo.toml

@@ -2,7 +2,7 @@
 name = "tokio-imap"
 version = "0.5.0"
 edition = "2021"
-rust-version = "1.67"
+rust-version = "1.70"
 description = "Tokio-based IMAP protocol (client, for now) implementation"
 documentation = "https://docs.rs/tokio-imap"
 keywords = ["imap", "tokio"]