Buid nim-waku node as separate ci step

So it's easily visible why a run takes longer and an update of the
submodule does not oddly increase the
test step duration.

.github/workflows/ci.yml

@@ -22,6 +22,7 @@ jobs:
         run: cd nim-waku && echo "::set-output name=ref::$(git rev-parse HEAD)"
 
       - name: Cache nim-waku binary
+        id: cache-nim-waku
         uses: actions/cache@v2
         with:
           path: |
@@ -29,6 +30,13 @@ jobs:
             ./nim-waku/vendor/rln/target/debug
           key: nim-waku-build-v2-${{ steps.nim-waku-head.outputs.ref }}
 
+        # This would have been done part of npm pretest but it gives better
+        # visibility in the CI if done as a separate step
+      - name: Build wakunode2
+        if: steps.cache-nim-waku.outputs.cache-hit != 'true'
+        shell: bash
+        run: cd nim-waku && make wakunode2
+
       - name: Install bufbuild
         uses: mu-io/setup-buf@v1beta
         with: