CI: Update to GITHUB_OUTPUT syntax

.github/workflows/linux-build.yml

@@ -30,7 +30,7 @@ jobs:
     steps:
     - name: Get current date as package key
       id: pkg_key
-      run: echo "::set-output name=key::$(date +'%W')"
+      run: echo "key=$(date +'%W')" >> $GITHUB_OUTPUT
 
     - name: Checkout repository
       uses: actions/checkout@v3
@@ -58,7 +58,7 @@ jobs:
     # Fetch xmake dephash
     - name: Retrieve dependencies hash
       id: dep_hash
-      run: echo "::set-output name=hash::$(xmake l utils.ci.packageskey)"
+      run: echo "hash=$(xmake l utils.ci.packageskey)" >> $GITHUB_OUTPUT
 
     # Cache xmake dependencies
     - name: Retrieve cached xmake dependencies