maybe use 22.04

Author: robtfm

.github/workflows/rust.yml

@@ -38,7 +38,7 @@ jobs:
 
   test-ubuntu:
     name: Test Suite (Ubuntu)
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v2
       - uses: dtolnay/rust-toolchain@stable