Replace pkg_resources version lookup with importlib.metadata

docs/conf.py

@@ -88,11 +88,10 @@ if on_rtd:
     ]
     sys.modules.update((mod_name, Mock()) for mod_name in MOCK_MODULES)
 
-
-from pkg_resources import get_distribution, DistributionNotFound
+from importlib.metadata import version as package_version
 
 # The full version, including alpha/beta/rc tags.
-release = get_distribution('ocrmypdf').version
+release = package_version('ocrmypdf').version
 version = '.'.join(release.split('.')[:2])
 
 

src/ocrmypdf/_version.py

@@ -5,9 +5,9 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 
-import pkg_resources
+from importlib.metadata import version as _package_version
 
 PROGRAM_NAME = 'ocrmypdf'
 
 # Official PEP 396
-__version__ = pkg_resources.get_distribution('ocrmypdf').version
+__version__ = _package_version('ocrmypdf')