ci: Use GITHUB_OUTPUT envvar instead of set-output command (#3533)

Co-authored-by: Garrett Campbell <[email protected]>

.github/workflows/build-vsix.yml

@@ -23,7 +23,7 @@ jobs:
 
       - name: Get Short SHA
         id: get-short-sha
-        run: echo "::set-output name=sha::$(git rev-parse --short ${GITHUB_SHA})"
+        run: echo "sha=$(git rev-parse --short ${GITHUB_SHA})" >> $GITHUB_OUTPUT
 
       - name: Update the package version
         uses: jacobtomlinson/gha-find-replace@master