ci(size): bump checkout and size-limit-action versions

actions/checkout@v1 is six years stale; pin size-limit-action to
v1.8.0 instead of the floating v1 tag and add setup-node so the
action's npm install has a consistent Node version.

Author: lakhansamani

.github/workflows/size.yml

@@ -6,7 +6,10 @@ jobs:
     env:
       CI_JOB_NUMBER: 1
     steps:
-      - uses: actions/checkout@v1
-      - uses: andresz1/size-limit-action@v1
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+      - uses: andresz1/size-limit-action@v1.8.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}