admin: pass --use-feature=2020-resolver to pip

to silence the warning like

follow the suggestion from pip

ERROR: After October 2020 you may experience errors when installing or updating packages. This is because pip will change the way that it resolves dependency conflicts.

We recommend you use --use-feature=2020-resolver to test your packages with the new resolver before it becomes the default.

Fixes: https://tracker.ceph.com/issues/47636
Signed-off-by: Kefu Chai <kchai@redhat.com>
(cherry picked from commit bc00a8feb0d2f4ddf14401e2b551fddff622d1de)

diff --git a/admin/build-doc b/admin/build-doc
index aa990ac7111a29e7c97fc0da0c9b48c802fec887..aa8baae6c34d5a86a611704d860c9a997e3e7660 100755 (executable)
--- a/admin/build-doc
+++ b/admin/build-doc
@@ -59,7 +59,7 @@ cd build-doc
 if [ ! -e $vdir ]; then
     virtualenv --python=python3 $vdir
 fi
-$vdir/bin/pip install --quiet -r $TOPDIR/admin/doc-requirements.txt -r $TOPDIR/admin/doc-python-common-requirements.txt
+$vdir/bin/pip install --use-feature=2020-resolver --quiet -r $TOPDIR/admin/doc-requirements.txt -r $TOPDIR/admin/doc-python-common-requirements.txt
 
 install -d -m0755 \
     $TOPDIR/build-doc/output/html \