CI: test on node 15 (#709)

Author: IvanGoncharov

.github/workflows/ci.yml

@@ -116,7 +116,7 @@ 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

@@ -8,6 +8,7 @@
  "graphql": "14.7.0",
  "node-10": "npm:node@10.x.x",
  "node-12": "npm:node@12.x.x",
- "node-14": "npm:node@14.x.x"
+ "node-14": "npm:node@14.x.x",
+ "node-15": "npm:node@15.x.x"
  }
 }