### What changes were proposed in this pull request?
For a bit of background,
PIP packaging test started to fail (see [this logs](https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/120218/testReport/)) as of setuptools 46.1.0 release. In https://github.com/pypa/setuptools/issues/1424, they decided to don't keep the modes in `package_data`.
In PySpark pip installation, we keep the executable scripts in `package_data` fc4e56a54c/python/setup.py (L199-L200), and expose their symbolic links as executable scripts.
So, the symbolic links (or copied scripts) executes the scripts copied from `package_data`, which doesn't have the executable permission in its mode:
```
/tmp/tmp.UmkEGNFdKF/3.6/bin/spark-submit: line 27: /tmp/tmp.UmkEGNFdKF/3.6/lib/python3.6/site-packages/pyspark/bin/spark-class: Permission denied
/tmp/tmp.UmkEGNFdKF/3.6/bin/spark-submit: line 27: exec: /tmp/tmp.UmkEGNFdKF/3.6/lib/python3.6/site-packages/pyspark/bin/spark-class: cannot execute: Permission denied
```
The current issue is being tracked at https://github.com/pypa/setuptools/issues/2041
</br>
For what this PR proposes:
It sets the upper bound in PR builder for now to unblock other PRs. _This PR does not solve the issue yet. I will make a fix after monitoring https://github.com/pypa/setuptools/issues/2041_
### Why are the changes needed?
It currently affects users who uses the latest setuptools. So, _users seem unable to use PySpark with the latest setuptools._ See also https://github.com/pypa/setuptools/issues/2041#issuecomment-602566667
### Does this PR introduce any user-facing change?
It makes CI pass for now. No user-facing change yet.
### How was this patch tested?
Jenkins will test.
Closes#27995 from HyukjinKwon/investigate-pip-packaging.
Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
c181c45f86