ARROW-11472: [Python][CI] Temporary pin numpy on kartothek integratio…

…n builds

Closes #9396 from jorisvandenbossche/ARROW-11472-kartothek-pin-numpy

Authored-by: Joris Van den Bossche <jorisvandenbossche@gmail.com>
Signed-off-by: Uwe L. Korn <uwe.korn@quantco.com>

ci/docker/conda-python-kartothek.dockerfile

@@ -38,7 +38,9 @@ RUN conda install -c conda-forge -q \
         storefact \
         toolz \
         urlquote \
-        zstandard && \
+        zstandard \
+        # temporary pin for numpy (see https://issues.apache.org/jira/browse/ARROW-11472)
+        numpy=1.19 && \
     conda clean --all
 
 ARG kartothek=latest