ci: fix node@6

Author: alexander-akait

.github/workflows/test.yml

@@ -46,9 +46,13 @@ jobs:
           node-version: ${{ matrix.node-version }}
           architecture: ${{ steps.calculate_architecture.outputs.result }}
           cache: npm
+      # npm is fully broken for Node.js@6
+      - name: Install old versions (optional)
+        run: yarn
+        if: matrix.node-version == '6.x'
       - name: Install dependencies
         run: npm install
-        if: matrix.node-version == '6.x' || matrix.node-version == '8.x' || matrix.node-version == '10.x' || matrix.node-version == '12.x' || matrix.node-version == '14.x'
+        if: matrix.node-version == '8.x' || matrix.node-version == '10.x' || matrix.node-version == '12.x' || matrix.node-version == '14.x'
       - name: Install dependencies
         run: npm ci
         if: matrix.node-version != '6.x' && matrix.node-version != '8.x' && matrix.node-version != '10.x' && matrix.node-version != '12.x' && matrix.node-version != '14.x'