doc(conf): update to use importlib.metadata

doc/conf.py

 #!/usr/bin/env python
 # vim: set fileencoding=utf-8 :
 
+import importlib.metadata
 import os
+import time
 
-import pkg_resources
+import sphinx_rtd_theme
 
 # -- General configuration -----------------------------------------------------
 
@@ -41,7 +43,7 @@ if os.path.exists("nitpick-exceptions.txt"):
         dtype, target = line.split(None, 1)
         target = target.strip()
         try:  # python 2.x
-            target = unicode(target)
+            target = unicode(target)  # type: ignore
         except NameError:
             pass
         nitpick_ignore.append((dtype, target))
@@ -74,21 +76,20 @@ master_doc = "index"
 
 # General information about the project.
 project = "bob.learn.em"
-import time
 
 copyright = "%s, Idiap Research Institute" % time.strftime("%Y")
 
 # Grab the setup entry
-distribution = pkg_resources.require(project)[0]
+distribution = importlib.metadata.version(project)
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
 # The short X.Y version.
-version = distribution.version
+version = distribution
 # The full version, including alpha/beta/rc tags.
-release = distribution.version
+release = distribution
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -134,7 +135,6 @@ owner = ["Idiap Research Institute"]
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-import sphinx_rtd_theme
 
 html_theme = "sphinx_rtd_theme"