Remove incorrect test value.

Author: vthg2themax

.github/workflows/test.yml

@@ -21,9 +21,6 @@ jobs:
           - os: windows-latest
             target: x86_64-pc-windows-msvc
             toolchain: beta
-          - os: ubuntu-latest
-            target: x86_64-unknown-linux-gnu
-            toolchain: 1.89.0 # MSRV
           - os: ubuntu-latest
             deps: sudo apt update ; sudo apt install gcc-multilib
             target: i686-unknown-linux-gnu