build: Pin hatchling version

Building a specific release with specific build tools feels like correct
choice for reproducibility in general. It's also practically required
as the hatchling version is embedded in the WHEEL file: this means
updating the build tool modifies the resulting build artifact.

Pin hatchling version. This version should be kept up-to-date: my
working assumption is that Dependabot will handle it.

Signed-off-by: Jussi Kukkonen <jkukkonen@vmware.com>

Author: Jussi Kukkonen

pyproject.toml

@@ -1,6 +1,6 @@
-# Build-system section
 [build-system]
-requires = ["hatchling>=0.21.0"]
+# hatchling pinned for reproducibility: version should be kept up-to-date
+requires = ["hatchling==0.22.0"]
 build-backend = "hatchling.build"
 
 [project]