Update changelog

Author: RKrahl

doc/src/changelog.rst

@@ -2,16 +2,23 @@ History of changes to pytest-dependency
 =======================================
 
 dev (not yet released)
+    Incompatible changes
+      + Drop support for Python 2.
+
     Bug fixes and minor changes
       + `#40`_: add logging.
       + `#50`_, `#51`_: test suite incompatibility with pytest 6.2.0.
       + `#58`_: declare the type of automark_dependency ini-option
 	correctly as bool.
 
+    Internal
+      + `#75`_: review build tool chain.
+
 .. _#40: https://github.com/RKrahl/pytest-dependency/issues/40
 .. _#50: https://github.com/RKrahl/pytest-dependency/issues/50
 .. _#51: https://github.com/RKrahl/pytest-dependency/pull/51
 .. _#58: https://github.com/RKrahl/pytest-dependency/pull/58
+.. _#75: https://github.com/RKrahl/pytest-dependency/pull/75
 
 0.5.1 (2020-02-14)
     Bug fixes and minor changes