Bumps google-auth-oauthlib dependency restriction to support up to version 1.0 (#6246)

* Motivation for features / changes
As requested and noted in #6197, we can bump this restriction, which is
currently affecting compatibility of TB with dependency requirements
from other packages. After the OOB auth flow migration, this should be
possible.

* Technical description of changes
Just bump the restriction for `google-auth-oauthlib` in our
`requirements.txt` file, to support newer versions.

* Detailed steps to verify changes work correctly (as executed by you)
Executed the auth flows (both the console-only one, and the one that
uses a browser in the same machine), and validated that they work as
before with the newer version.

Author: arcra

tensorboard/pip_package/requirements.txt

@@ -19,7 +19,7 @@ absl-py >= 0.4
 # NOTE: this version should be >= the grpc version in our WORKSPACE file.
 grpcio >= 1.48.2
 google-auth >= 1.6.3, < 3
-google-auth-oauthlib >= 0.4.1, < 0.5
+google-auth-oauthlib >= 0.5, < 1.1
 markdown >= 2.6.8
 numpy >= 1.12.0
 # NOTE: this version must be >= the protoc version in our WORKSPACE file.