v21.1.1

Fix

• Linkage errors in BetheHeitlerApprox.hpp [backport #1777 to develop/v21.1.x] (#1800) (12548a7) (@acts-project-service)
• Remove CustomDefaultLogger.cpp-entry from docs (#1735) (bfe770e) (@AJPfleger)

Ci

• Change how we run python based check jobs (#1799) (e728d54) (@paulgessinger)