ci: Use GITHUB_OUTPUT envvar instead of set-output command

.github/workflows/build.yml

@@ -24,12 +24,12 @@ jobs:
       - name: Extract current branch name
         shell: bash
         # bash pattern expansion to grab branch name without slashes
-        run: ref="${GITHUB_REF#refs/heads/}" && echo "::set-output name=branch::${ref////-}"
+        run: ref="${GITHUB_REF#refs/heads/}" && echo "branch=${ref////-}" >> $GITHUB_OUTPUT
         id: ref
 
       - name: Set outputs
         id: vars
-        run: echo "::set-output name=sha_short::$(git rev-parse --short HEAD)"
+        run: echo "sha_short=$(git rev-parse --short HEAD)" >> $GITHUB_OUTPUT
       - name: Check outputs
         run: echo ${{ steps.vars.outputs.sha_short }}