Dependencies: restrict pydantic to at least 1.10.8

The release of `typing_extensions` version `4.6.0` highlighted a bug in
`pydantic` related to the `Literal` type for Python versions 3.8 and 3.9.
This was fixed in `pydantic` version `1.10.8`.

Here the version of `pydantic` is set to be a compatible release with `1.10`
but at least `1.10.8`.

pyproject.toml

@@ -28,7 +28,7 @@ dependencies = [
     'importlib_resources',
     'jsonschema',
     'numpy',
-    'pydantic',
+    'pydantic~=1.10,>=1.10.8',
     'packaging',
     'qe-tools~=2.0',
     'xmlschema~=1.2,>=1.2.5'