fix: use @bahmutov/npm-install in templates' CI

- have been using this internally for about 6 months and I've personally
  contributed bugfixes and optimizations to it, so should be good to
  use by general users too
  - it's a good bit less configuration, which is particularly better for
    beginners, but even for advanced users, it means that improvements
    are shared out to all users
  - I also recommended it in an actions/cache issue about needing too
    much config already too, which I wouldn't have done if I weren't
    confident in its usage now

- this properly caches node_modules by using ~/.npm or Yarn's cache dir
  as recommended, instead of `node_modules` itself, which is not
  - c.f. https://github.com/actions/cache/blob/main/examples.md#node---npm

- it's also not susceptible to the `**/yarn.lock` issue that was
  reported because it caches the _one_ lockfile directly instead of
  potentially multiple lockfiles

templates/basic/.github/workflows/main.yml

@@ -13,16 +13,8 @@ jobs:
         with:
           node-version: 12.x
 
-      - name: Use cached node_modules
-        uses: actions/cache@v2
-        with:
-          path: node_modules
-          key: nodeModules-${{ hashFiles('**/yarn.lock') }}
-          restore-keys: |
-            nodeModules-
-
-      - name: Install dependencies
-        run: yarn install --frozen-lockfile
+      - name: Install deps and build (with cache)
+        uses: bahmutov/npm-install@v1
 
       - name: Lint
         run: yarn lint

templates/react-with-storybook/.github/workflows/main.yml

@@ -13,16 +13,8 @@ jobs:
         with:
           node-version: 12.x
 
-      - name: Use cached node_modules
-        uses: actions/cache@v2
-        with:
-          path: node_modules
-          key: nodeModules-${{ hashFiles('**/yarn.lock') }}
-          restore-keys: |
-            nodeModules-
-
-      - name: Install dependencies
-        run: yarn install --frozen-lockfile
+      - name: Install deps and build (with cache)
+        uses: bahmutov/npm-install@v1
 
       - name: Lint
         run: yarn lint

templates/react/.github/workflows/main.yml

@@ -13,16 +13,8 @@ jobs:
         with:
           node-version: 12.x
 
-      - name: Use cached node_modules
-        uses: actions/cache@v2
-        with:
-          path: node_modules
-          key: nodeModules-${{ hashFiles('**/yarn.lock') }}
-          restore-keys: |
-            nodeModules-
-
-      - name: Install dependencies
-        run: yarn install --frozen-lockfile
+      - name: Install deps and build (with cache)
+        uses: bahmutov/npm-install@v1
 
       - name: Lint
         run: yarn lint