fix: remove deprecated github env

.github/workflows/linuxpackage.yml

@@ -21,12 +21,15 @@ jobs:
           ruby-version: 2.6
 
       - name: Retrieve release version
-        run: echo "::set-env name=RELEASE_VERSION::${GITHUB_REF/refs\/tags\/v/}"
+        run: |
+          echo "RELEASE_VERSION=${GITHUB_REF/refs\/tags\/v/}" >> $GITHUB_ENV
 
       - name: Build package
         run: |
           set -x
 
+          echo "Release version: ${{ env.RELEASE_VERSION }}"
+
           sudo apt-get -yqq install libpq-dev build-essential
           gem install --no-document fpm
           fpm --version