Task #3405392: Cleanup how we define variables, opt into more verbose results

Authored-by: dww (Derek Wright) <git@dwwright.net>

.gitlab-ci.yml

@@ -21,14 +21,12 @@ include:
 # Docs at https://git.drupalcode.org/project/gitlab_templates/-/blob/1.0.x/includes/include.drupalci.variables.yml
 ################
 variables:
-    OPT_IN_TEST_PREVIOUS_MINOR:
-        value: '1'
-
-    OPT_IN_TEST_NEXT_MINOR:
-        value: '1'
-
-    OPT_IN_TEST_PREVIOUS_MAJOR:
-        value: '1'
-
-    OPT_IN_TEST_MAX_PHP:
-        value: '1'
+  # Broaden test coverage.
+  OPT_IN_TEST_PREVIOUS_MINOR: 1
+  OPT_IN_TEST_NEXT_MINOR: 1
+  OPT_IN_TEST_PREVIOUS_MAJOR: 1
+  OPT_IN_TEST_MAX_PHP: 1
+  # Show more log output
+  _PHPUNIT_EXTRA: --verbose
+  # Convenient, and we have no secrets.
+  _SHOW_ENVIRONMENT_VARIABLES: 1