test: remove CI pinned to an explicit MSRV (#547)

Author: molpopgen

.github/workflows/test32bit.yml

@@ -16,7 +16,6 @@ jobs:
         os: [ubuntu-latest]
         rust:
           - stable
-          - 1.71.0
     steps:
       - name: Cancel Previous Runs
         uses: styfle/cancel-workflow-action@0.11.0

.github/workflows/tests.yml

@@ -16,7 +16,6 @@ jobs:
         os: [ubuntu-latest, macos-latest]
         rust:
           - stable
-          - 1.71.0
     steps:
       - name: Cancel Previous Runs
         uses: styfle/cancel-workflow-action@0.11.0
@@ -67,7 +66,6 @@ jobs:
       matrix:
         rust:
           - stable
-          - 1.71.0
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@v1