[core] implement support for run-time dependency version checking (#8645)

* implement support for run-time dependency version checking

* try not escaping !

* use findall that works on py36

* small tweaks

* autoformatter worship

* simplify

* shorter names

* add support for non-versioned checks

* add deps

* revert

* tokenizers not required, check version only if installed

* make a proper distutils cmd and add make target

* tqdm must be checked before tokenizers

* workaround the DistributionNotFound peculiar setup

* handle the rest of packages in setup.py

* fully sync setup.py's install_requires - to check them all

* nit

* make install_requires more readable

* typo

* Update setup.py

Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

* restyle

* add types

* simplify

* simplify2

Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

examples/lightning_base.py

@@ -4,11 +4,9 @@ import os
 from pathlib import Path
 from typing import Any, Dict
 
-import packaging
 import pytorch_lightning as pl
 from pytorch_lightning.utilities import rank_zero_info
 
-import pkg_resources
 from transformers import (
     AdamW,
     AutoConfig,
@@ -30,21 +28,12 @@ from transformers.optimization import (
     get_linear_schedule_with_warmup,
     get_polynomial_decay_schedule_with_warmup,
 )
+from transformers.utils.versions import require_version_examples
 
 
 logger = logging.getLogger(__name__)
 
-
-def require_min_ver(pkg, min_ver):
-    got_ver = pkg_resources.get_distribution(pkg).version
-    if packaging.version.parse(got_ver) < packaging.version.parse(min_ver):
-        logger.warning(
-            f"{pkg}>={min_ver} is required for a normal functioning of this module, but found {pkg}=={got_ver}. "
-            "Try: pip install -r examples/requirements.txt"
-        )
-
-
-require_min_ver("pytorch_lightning", "1.0.4")
+require_version_examples("pytorch_lightning>=1.0.4")
 
 MODEL_MODES = {
     "base": AutoModel,