Bump MSRV to 1.68

To fix CI, failing on polling v3.11.0.

Author: dcz

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        rust: ['1.65.0', 'stable', 'beta']
+        rust: ['1.71.0', 'stable', 'beta']
     runs-on: ubuntu-latest
 
     steps:

Cargo.toml

@@ -6,7 +6,7 @@ documentation = "https://smithay.github.io/client-toolkit"
 repository = "https://github.com/smithay/client-toolkit"
 license = "MIT"
 edition = "2021"
-rust-version = "1.65"
+rust-version = "1.71"
 categories = ["gui"]
 keywords = ["wayland", "client"]
 description = "Toolkit for making client wayland applications."