pin sphinx-hoverxref version to 1.4.x, where x>2

For reference: https://stackoverflow.com/questions/39590187/in-requirements-txt-what-does-tilde-equals-mean

Author: echedey-ls

pyproject.toml

@@ -66,7 +66,7 @@ doc = [
     'sphinx-toggleprompt == 0.5.2',
     'sphinx-favicon',
     'solarfactors',
-    'sphinx-hoverxref',
+    'sphinx-hoverxref ~= 1.4.2',
 ]
 test = [
     'pytest',