ci: disable from-forge for now since we aren't using them

.gitlab-ci.yml

@@ -215,7 +215,7 @@ test-cube-skeleton:
     - tox
     - '[ "$(hg status | wc -l)" = 0 ]'
 
-py3-from-forge-server:
+.py3-from-forge-server:
   interruptible: true
   rules:
     - changes:
@@ -241,7 +241,7 @@ py3-from-forge-server:
   script:
     - tox -e py3-from-forge-server
 
-py3-from-forge-web:
+.py3-from-forge-web:
   interruptible: true
   rules:
     - changes:
@@ -266,7 +266,7 @@ py3-from-forge-web:
       junit: /builds/cubicweb/cubicweb/from-forge-web.xml
     expire_in: 2 weeks
 
-py3-from-forge-misc:
+.py3-from-forge-misc:
   interruptible: true
   rules:
     - changes: