ci: increase MSRV to 1.70.0

This is required by `anstyle v1.0.4` dependency.

.github/workflows/ci.yml

@@ -82,9 +82,9 @@ jobs:
           - os: macos-latest
             rust: 1.73.0
 
-          # Minimum Supported Rust Version = 1.67.0
+          # Minimum Supported Rust Version = 1.70.0
           - os: ubuntu-latest
-            rust: 1.67.0
+            rust: 1.70.0
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v3

Cargo.toml

@@ -3,7 +3,7 @@ name = "deltachat"
 version = "1.126.1"
 edition = "2021"
 license = "MPL-2.0"
-rust-version = "1.67"
+rust-version = "1.70"
 
 [profile.dev]
 debug = 0