build: convert ::set-output to $GITHUB_OUTPUT

Signed-off-by: Hidde Beydals <hello@hidde.co>

.github/workflows/cifuzz.yaml

@@ -23,7 +23,7 @@ jobs:
         go-version: 1.19.x
     - id: go-env
       run: |
-        echo "::set-output name=go-mod-cache::$(go env GOMODCACHE)"
+        echo "go-mod-cache=$(go env GOMODCACHE)" >> $GITHUB_OUTPUT
     - name: Restore Go cache
       uses: actions/cache@v3
       with: