show how to get package version

docs/usage.md

@@ -10,6 +10,13 @@ EchoSMs is available on [PyPi](https://pypi.org) as [`echosms`](https://pypi.org
 
 Some of the models in echoSMs use spheroidal wave functions. A high-accuracy implementation of these is available in the Python package [`spheroidalwavefunctions`](https://pypi.org/project/spheroidalwavefunctions/), as the versions provided by [scipy](https://docs.scipy.org/doc/scipy/reference/special.html#spheroidal-wave-functions) are insufficient. This should be installed automatically when you install echosms, but note that `spheroidalwavefunctions` is currently only available for Linux and Windows on x86_64 CPU architectures (create an [issue](https://github.com/ices-tools-dev/echoSMs/issues) if you want it on a system that is not currently supported).
 
+## Version
+
+The installed version of echosms can be printed with this code:
+
+    import importlib
+    print(importlib.metadata.version('echosms'))
+
 ## Model overview
 
 Currently, the following models are available in echoSMs:

pyproject.toml

@@ -1,13 +1,12 @@
 [build-system]
-requires = ["hatchling"]
+requires = ["hatchling", 'hatch-vcs']
 build-backend = "hatchling.build"
 
 [tool.hatch.build.targets.wheel]
 packages = ["src/echosms"]
 
 [project]
 name = 'echosms'
-version = '0.1.11'
 license = {file = "LICENSE"}
 keywords = ["acoustic", "backscatter", "model"]
 authors = [
@@ -37,6 +36,10 @@ classifiers = [
     'Programming Language :: Python :: 3.12',
     'Topic :: Scientific/Engineering',
 ]
+dynamic = [ 'version']
+
+[tool.hatch.version]
+source = 'vcs'
 
 [project.optional-dependencies]
 dev = [