use ($()) to only use the value not call comd again in .gitlab-ci.yml

.gitlab-ci.yml

 image: ${CI_REGISTRY_IMAGE}/buildimage
 before_script:
   - export ARCH=all
-  - export VERSION=$(dpkg-parsechangelog -S version)
-  - export PKGNAME=$(awk '/^Package:/ { print $2 }' debian/control)
+  - export VERSION=($(dpkg-parsechangelog -S version))
+  - export PKGNAME=($(awk '/^Package:/ { print $2 }' debian/control))
   - echo $ARCH
   - echo $VERSION
   - echo $PKGNAME