Prepare for major version bump

Recent model changes have adjusted the return type of some methods
and made certain behavior more strict. Though there probably aren't
affected clients right now, this is technically
backwards-incompatible, so the major version should be bumped.

Author: rohanpm

CHANGELOG.md

@@ -7,7 +7,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-- n/a
+### Changed
+- **API break**: types of fields on model objects are now strictly validated
+  during construction.
+- **API break**: objects documented as immutable are now more deeply immutable;
+  it is no longer possible to mutate list fields on these objects.
+- **API break**: fixed inconsistencies on collection model fields. All fields
+  previously declared as tuples have been updated to use (immutable) lists.
+
+
+### Fixed
+- **API break**: `MaintenanceReport.last_updated`, `MaintenanceEntry.started`
+  are now `datetime` objects as documented. In previous versions, these were
+  documented as datetimes but implemented as `str`.
 
 ## [1.5.0] - 2019-09-03
 

setup.py

@@ -21,7 +21,7 @@ def get_requirements():
 
 setup(
     name="pubtools-pulplib",
-    version="1.5.0",
+    version="2.0.0",
     packages=find_packages(exclude=["tests"]),
     package_data={"pubtools.pulplib._impl.schema": ["*.yaml"]},
     url="https://github.com/release-engineering/pubtools-pulplib",