Modernize python package version specifiers (espressomd#4709)

Description of changes:
- fix import errors in several tests, tutorials and benchmarks due to API changes in setuptools >= 67.3.0

doc/tutorials/constant_pH/constant_pH.ipynb

@@ -137,10 +137,10 @@
     "plt.rcParams.update({'font.size': 18})\n",
     "\n",
     "import numpy as np\n",
-    "import setuptools\n",
+    "import pkg_resources\n",
     "import pint  # module for working with units and dimensions\n",
     "import time\n",
-    "assert setuptools.version.pkg_resources.packaging.specifiers.SpecifierSet('>=0.10.1').contains(pint.__version__), \\\n",
+    "assert pkg_resources.packaging.specifiers.SpecifierSet('>=0.10.1').contains(pint.__version__), \\\n",
     "  f'pint version {pint.__version__} is too old: several numpy operations can cast away the unit'\n",
     "\n",
     "import espressomd\n",

maintainer/benchmarks/mc_acid_base_reservoir.py

@@ -24,7 +24,7 @@
 import espressomd
 import espressomd.electrostatics
 import espressomd.reaction_methods
-import setuptools
+import pkg_resources
 import argparse
 
 parser = argparse.ArgumentParser(description="Benchmark MC simulations in the grand-reaction ensemble. "
@@ -45,7 +45,7 @@
 # process and check arguments
 assert args.particles_per_core >= 100, "you need to use at least 100 particles per core to avoid finite-size effects in the simulation"
 espressomd.assert_features(['WCA', 'ELECTROSTATICS'])
-assert setuptools.version.pkg_resources.packaging.specifiers.SpecifierSet('>=0.10.1').contains(pint.__version__), \
+assert pkg_resources.packaging.specifiers.SpecifierSet('>=0.10.1').contains(pint.__version__), \
     f'pint version {pint.__version__} is too old: several numpy operations can cast away the unit'
 
 

testsuite/python/unittest_decorators.py

@@ -19,7 +19,7 @@
 
 import sys
 import importlib
-import setuptools
+import pkg_resources
 import unittest
 
 import espressomd
@@ -74,7 +74,7 @@ def skipIfUnmetModuleVersionRequirement(module, version_requirement):
         _module = importlib.import_module(module)
     except ImportError:
         return skipIfMissingModules(module)
-    if not setuptools.version.pkg_resources.packaging.specifiers.SpecifierSet(
+    if not pkg_resources.packaging.specifiers.SpecifierSet(
             version_requirement).contains(_module.__version__):
         return unittest.skip(
             "Skipping test: version requirement not met for module {}".format(module))