chore: use pnpm instead of yarn

.github/workflows/ci.yaml

@@ -1,18 +1,50 @@
-on: pull_request
+on:
+  - pull_request
+
 jobs:
   lint_and_test:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - uses: pnpm/action-setup@v4
+        name: Install pnpm
+        with:
+          version: 8
+          run_install: false
+
+      - name: Get pnpm store directory
+        shell: bash
+        run: |
+          echo "STORE_PATH=$(pnpm store path --silent)" >> $GITHUB_ENV
 
-      - uses: actions/[email protected]
+      - uses: actions/cache@v4
+        name: Setup pnpm cache
         with:
-          node-version: '20.11'
+          path: ${{ env.STORE_PATH }}
+          key: ${{ runner.os }}-pnpm-store-${{ hashFiles('**/pnpm-lock.yaml') }}
+          restore-keys: |
+            ${{ runner.os }}-pnpm-store-
+
+      - name: Install dependencies
+        run: pnpm install
+
+      - name: Run linter
+        run: pnpm lint:check
 
-      - run: yarn
-      - run: yarn lint:check
+      - name: Run formatter
+        run: pnpm format
 
-      - run: yarn test
+      - name: Run unit tests
+        run: pnpm test
 
-      - run: yarn build
+      - name: Run build 
+        run: pnpm build 
+

README.md

@@ -8,7 +8,7 @@ You can simply add the `witnet-radon-js` package as a
 dependency with npm:
 
 ```console
-yarn add witnet-radon-js
+pnpm add witnet-radon-js
 ```
 
 

package.json

@@ -20,7 +20,7 @@
     "lint": "prettier --write '{src,test}/**/*.{t,j}s'",
     "lint:check": "prettier --check '{src,test}/**/*.{t,j}s'",
     "test": "vitest",
-    "prepare": "npm run build"
+    "prepare": "pnpm run build"
   },
   "keywords": [
     "radon",