TST: lib/test: skip_ci: detect dpkg-buildpackage environments

see https://lists.cert.at/pipermail/intelmq-dev/2021-October/000528.html
and following

Author: Sebastian Wagner

CHANGELOG.md

@@ -82,6 +82,8 @@ CHANGELOG
 
 ### Tests
 - Add GitHub Action to run regexploit on all Python, JSON and YAML files (PR#2059 by Sebastian Wagner).
+- `intelmq.lib.test`:
+  - Decorator `skip_ci` also detects `dpkg-buildpackage` environments by checking the environment variable `DEB_BUILD_ARCH` (PR#2123 by Sebastian Wagner).
 
 ### Tools
 

intelmq/lib/test.py

@@ -96,7 +96,8 @@ def skip_exotic():
 
 
 def skip_ci():
-    return unittest.skipIf(os.getenv('CI') == 'true', 'Test disabled on CI.')
+    return unittest.skipIf(os.getenv('CI') == 'true' or os.environ.get('DEB_BUILD_ARCH'),
+                           'Test disabled on CI.')
 
 
 def skip_build_environment():