Bumping the version before the release (#79)

Author: PietropaoloFrisoni

CHANGELOG.md

@@ -1,20 +1,10 @@
-# Release 0.40.0-dev
-
-### New features since last release
-
-### Improvements 🛠
+# Release 0.40.0
 
 ### Breaking changes 💔
 
 * The ``qml.QubitStateVector`` template has been removed. Instead, use :class:`~pennylane.StatePrep`.
   [(#77)](https://github.com/PennyLaneAI/pennylane-aqt/pull/77)
 
-### Deprecations 👋
-
-### Documentation 📝
-
-### Bug fixes 🐛
-
 ### Contributors ✍️
 
 This release contains contributions from (in alphabetical order):

pennylane_aqt/_version.py

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