gitlab-ci: Tag lightweight jobs to reduce their latency

Lightweight CI runners have been introduced to run jobs which have low
resource consumption and do not need privileged containers to reduce costs
and latency, so let's use them.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

.gitlab-ci.yml

@@ -8,11 +8,15 @@ include:
 
 test-renderer:
   stage: test
+  tags:
+    - lightweight
   script:
     - python3 -m unittest discover -v
 
 render-pages:
   stage: test
+  tags:
+    - lightweight
   script:
     - ./atc -d ${release}/ --index-page test-cases/
   artifacts:
@@ -63,6 +67,8 @@ deploy-pages:
 
 .submit-tests-apt:
   extends: .submit-tests
+  tags:
+    - lightweight
   stage: deploy
   variables:
     profile_name: ${osname}-${type}-${architecture}-${board}
@@ -75,6 +81,8 @@ deploy-pages:
 
 .submit-tests-ostree:
   extends: .submit-tests
+  tags:
+    - lightweight
   stage: deploy
   variables:
     profile_name: ${osname}_ostree-${type}-${architecture}-${board}