ci: release: Use output parameter file

This commit updates the workflow to use the output parameter file
(`GITHUB_OUTPUT`) instead of the stdout-based output parameter setting,
which is now deprecated by GitHub and will be removed in the near
future.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>

.github/workflows/release.yml

@@ -16,7 +16,8 @@ jobs:
 
       - name: Get the version
         id: get_version
-        run: echo ::set-output name=VERSION::${GITHUB_REF#refs/tags/}
+        run: |
+          echo "VERSION=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
 
       - name: REUSE Compliance Check
         uses: fsfe/reuse-action@v1