add [skip tests] and [skip scan] to skip CI stages

also lets you define SKIP_TESTS and/or SKIP_SCAN in pipeline variables
to skip testing or scanning

Author: nvjmayo

.nvidia-ci.yml

@@ -109,12 +109,20 @@ build:
 
 test:
   stage: test
+  except:
+    variables:
+    - $CI_COMMIT_MESSAGE =~ /\[skip[ _-]tests?\]/i
+    - $SKIP_TESTS
   script:
     - *testdep_setup
     - *test_action
 
 scan:
   stage: scan
+  except:
+    variables:
+    - $CI_COMMIT_MESSAGE =~ /\[skip[ _-]scan?\]/i
+    - $SKIP_SCAN
   script:
     - *builddep_setup
     - *python_setup