Updated minimal version of py_tools_ds (fixes issue #41 (Sporadic...

Updated minimal version of py_tools_ds (fixes issue #41

 (Sporadic AssertionErrors in case the matching window crosses the image edge)).
Signed-off-by: Daniel Scheffler <danschef@gfz-potsdam.de>

.gitlab-ci.yml

@@ -16,7 +16,7 @@ test_arosics:
     - conda install -c conda-forge cartopy  # FIXME remove as soon as docker container is rebuilt
 
     # update py_tools_ds and geoarray
-    # - pip install "py_tools_ds>=0.14.28"
+    # - pip install "py_tools_ds>=0.15.8"
     - pip install "geoarray>=0.9.0"
 
     # run tests