Pin protobuf version (#13177)

Author: akihironitta

pytorch_lightning/setup_tools.py

@@ -32,9 +32,10 @@ def _load_requirements(
     reqs = []
     for ln in lines:
         # filer all comments
+        comment = ""
         if comment_char in ln:
+            comment = ln[ln.index(comment_char) :]
             ln = ln[: ln.index(comment_char)]
-        comment = ln[ln.index(comment_char) :] if comment_char in ln else ""
         req = ln.strip()
         # skip directly installed dependencies
         if not req or req.startswith("http") or "@http" in req:

requirements/base.txt

@@ -8,3 +8,4 @@ torchmetrics>=0.4.1, <=0.7.2
 pyDeprecate>=0.3.1, <=0.3.2
 packaging>=17.0, <=21.3
 typing-extensions>=4.0.0, <4.2.1
+protobuf<=3.20.1  # strict. TODO: Remove after tensorboard gets compatible https://github.com/tensorflow/tensorboard/issues/5708