Bumping the version before the release (#205)

Author: PietropaoloFrisoni

CHANGELOG.md

@@ -1,8 +1,4 @@
-# Release 0.40.0-dev
-
-### New features since last release
-
-### Improvements 🛠
+# Release 0.40.0
 
 ### Breaking changes 💔
 
@@ -13,12 +9,6 @@
   in PennyLane 0.39, and is removed in PennyLane 0.40.
   [(#204)](https://github.com/PennyLaneAI/pennylane-cirq/pull/204)
 
-### Deprecations 👋
-
-### Documentation 📝
-
-### Bug fixes 🐛
-
 ### Contributors ✍️
 
 This release contains contributions from (in alphabetical order):

pennylane_cirq/_version.py

@@ -16,4 +16,4 @@
    Version number (major.minor.patch[-label])
 """
 
-__version__ = "0.40.0-dev"
+__version__ = "0.40.0"