more bors tweaks

bors-ng/bors-ng#1092 (comment)

.github/workflows/ci.yml

@@ -27,3 +27,25 @@ jobs:
       - run: cargo check --no-default-features
       - run: cargo check --no-default-features --features "use_alloc"
       - run: cargo test
+
+  # https://github.com/rust-lang/crater/blob/9ab6f9697c901c4a44025cf0a39b73ad5b37d198/.github/workflows/bors.yml#L125-L149
+  end-success:
+    name: bors build finished
+    if: success()
+    runs-on: ubuntu-latest
+    needs: [msrv,stable]
+
+    steps:
+      - name: Mark the job as successful
+        run: exit 0
+
+  end-failure:
+    name: bors build finished
+    if: "!success()"
+    runs-on: ubuntu-latest
+    needs: [msrv,stable]
+
+    steps:
+      - name: Mark the job as a failure
+        run: exit 1
+