chore(main): release 0.4.0

Author: release-please[bot]

CHANGELOG.md

@@ -1,5 +1,17 @@
 # Changelog
 
+## [0.4.0](https://github.com/googleapis/python-db-dtypes-pandas/compare/v0.3.1...v0.4.0) (2022-03-01)
+
+
+### ⚠ BREAKING CHANGES
+
+* dbdate and dbtime dtypes return NaT instead of None for missing values
+
+### Bug Fixes
+
+* use `pandas.NaT` for missing values in dbdate and dbtime dtypes ([#67](https://github.com/googleapis/python-db-dtypes-pandas/issues/67)) ([f903c2c](https://github.com/googleapis/python-db-dtypes-pandas/commit/f903c2c68da1629241cf3bf37e1226babae669f4))
+* use public pandas APIs where possible ([#60](https://github.com/googleapis/python-db-dtypes-pandas/issues/60)) ([e9d41d1](https://github.com/googleapis/python-db-dtypes-pandas/commit/e9d41d17b5d6a7d83c46e2497feb8e314545adcb))
+
 ### [0.3.1](https://www.github.com/googleapis/python-db-dtypes-pandas/compare/v0.3.0...v0.3.1) (2021-12-04)
 
 

db_dtypes/version.py

@@ -12,4 +12,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-__version__ = "0.3.1"
+__version__ = "0.4.0"