ci(pr.yml): Add a 32 bit runner test

.github/workflows/pr.yml

@@ -51,7 +51,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
         with:
-          fetch-depth: '0'
+          fetch-depth: "0"
       - uses: maidsafe/pr_size_checker@v2
         with:
           max_lines_changed: 200
@@ -151,6 +151,32 @@ jobs:
       - name: Cargo test
         run: cargo test --release
 
+  tests32:
+    name: Test 32bit
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      # Install Rust
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: i686-unknown-linux-gnu
+          override: true
+
+      # Cache.
+      - name: Cargo cache registry, index and build
+        uses: actions/cache@v2.1.4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-cache-${{ hashFiles('**/Cargo.lock') }}
+
+      # Run tests.
+      - name: Cargo test
+        run: cargo test --release
+
   # Test publish using --dry-run.
   test-publish:
     name: Test Publish