Delete minimal-versions CI, as there are no dependencies anymore

Author: dtolnay

.github/workflows/ci.yml

@@ -47,18 +47,6 @@ jobs:
       - uses: dtolnay/rust-toolchain@1.31.0
       - run: cargo check
 
-  minimal:
-    name: Minimal versions
-    needs: pre_ci
-    if: needs.pre_ci.outputs.continue
-    runs-on: ubuntu-latest
-    timeout-minutes: 45
-    steps:
-      - uses: actions/checkout@v3
-      - uses: dtolnay/rust-toolchain@nightly
-      - run: cargo -Z minimal-versions generate-lockfile
-      - run: cargo check --locked
-
   clippy:
     name: Clippy
     runs-on: ubuntu-latest