Remove NPM caching from CI - it's not doing anything

npm ci clears node_modules regardless, so this doesn't help!

Author: pimterry

.github/workflows/ci.yml

@@ -19,17 +19,6 @@ jobs:
         with:
           java-version: 11
 
-      - name: Get npm cache directory
-        id: npm-cache
-        run: |
-          echo "::set-output name=dir::$(npm config get cache)"
-      - uses: actions/cache@v2
-        with:
-          path: ${{ steps.npm-cache.outputs.dir }}
-          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
-          restore-keys: |
-            ${{ runner.os }}-node-
-
       - run: npm ci
 
       - name: Install test environment