ci: bump apify/actions/pnpm-install to v1.3.1 (#913)

Bumps the pinned `apify/actions/pnpm-install` composite action to
`v1.3.1`.

That release updates `actions/cache` to `v6.1.0`, so the action runs on
the Node.js 24 runtime. It clears the "Node.js 20 is deprecated" warning
that shows up on every CI run. For details, see apify/actions#29.

Author: vdusek

.github/workflows/_checks.yaml

@@ -86,7 +86,7 @@ jobs:
           node-version: ${{ env.NODE_VERSION }}
 
       - name: Install pnpm and website dependencies
-        uses: apify/actions/pnpm-install@v1.3.0
+        uses: apify/actions/pnpm-install@v1.3.1
         with:
           working-directory: website
 
@@ -107,7 +107,7 @@ jobs:
           node-version: ${{ env.NODE_VERSION }}
 
       - name: Install pnpm and website dependencies
-        uses: apify/actions/pnpm-install@v1.3.0
+        uses: apify/actions/pnpm-install@v1.3.1
         with:
           working-directory: website
 

.github/workflows/manual_release_docs.yaml

@@ -73,7 +73,7 @@ jobs:
         run: uv run poe install-dev
 
       - name: Install pnpm and website dependencies
-        uses: apify/actions/pnpm-install@v1.3.0
+        uses: apify/actions/pnpm-install@v1.3.1
         with:
           working-directory: website
 

.github/workflows/manual_version_docs.yaml

@@ -72,7 +72,7 @@ jobs:
         run: uv run poe install-dev
 
       - name: Install pnpm and website dependencies
-        uses: apify/actions/pnpm-install@v1.3.0
+        uses: apify/actions/pnpm-install@v1.3.1
         with:
           working-directory: website