CI: test on node 15

Author: IvanGoncharov

.github/workflows/ci.yml

@@ -145,7 +145,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node_version_to_setup: [10, 12, 14]
+        node_version_to_setup: [10, 12, 14, 15]
     steps:
       - name: Checkout repo
         uses: actions/checkout@v2

integrationTests/node/package.json

@@ -8,5 +8,6 @@
     "node-10": "npm:node@10.x.x",
     "node-12": "npm:node@12.x.x",
     "node-14": "npm:node@14.x.x"
+    "node-15": "npm:node@15.x.x"
   }
 }