Switch to lightweight runners

After switching to use JSON as format for the outcome of the different
steps in the dashboard the resources needed drop dramatically. In this
context the use of lightweight runners should be sufficient and it is
preferable to reduce costs.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

.gitlab-ci.yml

@@ -383,6 +383,8 @@ packaging-check-settings:
 
 packaging-check-invariants:
   stage: check
+  tags:
+    - lightweight
   before_script:
     - apt update && apt install -y --no-install-recommends
         python3-debian
@@ -414,6 +416,8 @@ packaging-check-invariants:
 
 packaging-updates:
   stage: plan
+  tags:
+    - lightweight
   before_script:
     - apt update && apt install -y --no-install-recommends
         devscripts
@@ -438,6 +442,8 @@ packaging-updates:
 
 packaging-updates-upstream-linux:
   stage: plan
+  tags:
+    - lightweight
   before_script:
     - apt update && apt install -y --no-install-recommends
         ca-certificates
@@ -463,8 +469,8 @@ packaging-updates-upstream-linux:
 
 .render:
   stage: render
-  #tags:
-  #  - lightweight
+  tags:
+    - lightweight
   before_script:
     - apt update && apt install -y --no-install-recommends
         python3-jinja2