Fix cross build test.

The cross build test checks that `Rand` can be cross built for mips.
The Rust project no longer provides binaries for that target.  Switch
to arm, as on the `master` branch.

Author: nwalfield

.github/workflows/test.yml

@@ -115,18 +115,16 @@ jobs:
       matrix:
         include:
           - os: ubuntu-latest
-            target: mips-unknown-linux-gnu
+            target: powerpc-unknown-linux-gnu
             toolchain: stable
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v6
       - name: Install toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@master
         with:
-          profile: minimal
           target: ${{ matrix.target }}
           toolchain: ${{ matrix.toolchain }}
-          override: true
       - name: Cache cargo plugins
         uses: actions/cache@v5
         with: