Fix YAML syntax

Author: marin-m

.github/workflows/packaging.yml

@@ -21,4 +21,4 @@ jobs:
       - name: Ensure metainfo.xml validity
         run: appstreamcli validate packaging/rootfs/usr/share/metainfo/re.fossplant.songrec.metainfo.xml
       - name: Build Debian package
-        run: bash -c 'rustup update && echo Using: $(rustup which cargo) / $(ls -l $(which cargo)) && ./packaging/ppa/build_binary_package.sh'
+        run: "bash -c 'rustup update && echo Using: $(rustup which cargo) / $(ls -l $(which cargo)) && ./packaging/ppa/build_binary_package.sh'"