Quote volume mount arg for the output dir

The directory might contain spaces.

Signed-off-by: James Slagle <jslagle@redhat.com>

Author: slagle

.github/workflows/edpm-bootc.yaml

@@ -70,7 +70,7 @@ jobs:
         build-args:
           EDPM_BASE_IMAGE=${{ env.EDPM_BASE_IMAGE }}
         extra-args:
-          --volume $(shell pwd)/output/yum.repos.d:/etc/yum.repos.d:rw,Z
+          --volume "$(shell pwd)/output/yum.repos.d:/etc/yum.repos.d:rw,Z"
         containerfiles: |
           ./bootc/Containerfile
         context: bootc