Add fpm to PATH

.github/workflows/release.yml

@@ -33,6 +33,7 @@ jobs:
         sudo apt-get update
         sudo apt-get install -y ruby-full
         gem install fpm
+        export PATH="$(ruby -e 'puts Gem.user_dir')/bin:$PATH"
     - name: Check fpm
       run: which fpm
     - name: Build Debian package