Merge pull request #29 from agriyakhetarpal/fix/gha-updates

Fix `save-state` deprecation warning, pin GitHub Actions to their SHAs, and remove unneeded steps

.github/workflows/deploy.yml

@@ -19,7 +19,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: Setup Python
         uses: actions/setup-python@v5
         with:
@@ -50,7 +50,7 @@ jobs:
         run: echo "live.sympy.org" > ./_output/CNAME
 
       - name: Upload (dist)
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@65c4c4a1ddee5b72f698fdd19549f0f0fb45cf08 # v4.6.0
         with:
           name: jupyterlite-demo-dist-${{ github.run_number }}
           path: ./_output
@@ -61,16 +61,14 @@ jobs:
     needs: build
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout
-        uses: actions/[email protected]
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
         with:
           name: jupyterlite-demo-dist-${{ github.run_number }}
           path: ./dist
           merge-multiple: true
 
       - name: Deploy
-        uses: JamesIves/github-pages-deploy-action@4.1.3
+        uses: JamesIves/github-pages-deploy-action@15de0f09300eea763baee31dff6c6184995c5f6a # v4.7.2
         with:
           branch: gh-pages
           folder: dist