Fix is_invocable_v

2.3.3

Fix is_invocable_v and add test coverage

2.3.2: Merge pull request #181 from boostorg/develop

• fix is_invocable for param-less lambdas
• fix is_invocable_r for void returns
• improve test coverage and CI

2.3.1

• allow top-level cv/ref on qualified_class_of
• fix bug for abominable function types with varargs
• update documentation

2.3.0

• improve test coverage
• allow pointers with top-level cv/ref on args, return_type, class_of, function_type, has_*, is_* (minus is_invocable*)
• allow function objects in volatile-qualified reference wrapper

2.2.1

• is_invocable returns false for abominable function types, rather than erroring
• function object references now supported
• better CI
• fixed links in documentation