disable redshift tests (#2238)

SUMMARY
See also: #2237
Blocking ansible-collections/amazon.aws#2517 because module_utils.botocore is triggering all the tests
ISSUE TYPE

Bugfix Pull Request

COMPONENT NAME
redshift
ADDITIONAL INFORMATION

Reviewed-by: Bikouo Aubin

tests/integration/targets/redshift/aliases

@@ -1,3 +1,6 @@
+# reason: broken
+# AWS no longer supports unencrypted Redshift clusters - tests need updating
+disabled
 time=35m
 cloud/aws
 redshift_info