Update Github actions (#80)

Especially cache v2 is deprecated and doesn't work anymore as of Feb 1 2025

Author: lfrancke

.github/workflows/build.yml

@@ -8,12 +8,12 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/setup-node@cdca7365b2dadb8aad0a33bc7601856ffabcc48e # v4.3.0
         with:
           node-version: '16'
       - name: Cache Node.js modules
-        uses: actions/cache@v2
+        uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
         with:
           path: ~/.npm
           key: ${{ runner.OS }}-node-${{ hashFiles('**/package-lock.json') }}