remove numbagg and numba from the upstream-dev CI (#7416)

* temporarily remove `numba` from the upstream-dev environment

* don't explicitly install the matplotlib dependency

* use `pip` to remove `numbagg`

* [test-upstream]

* remove `numba` and `numbagg` first [test-upstream]

Co-authored-by: Joe Hamman <joe@earthmover.io>

Author: keewis

ci/install-upstream-wheels.sh

@@ -1,5 +1,9 @@
 #!/usr/bin/env bash
 
+# temporarily (?) remove numbagg and numba
+pip uninstall -y numbagg
+conda uninstall -y numba
+# forcibly remove packages to avoid artifacts
 conda uninstall -y --force \
     numpy \
     scipy \
@@ -18,8 +22,6 @@ conda uninstall -y --force \
     flox \
     h5netcdf \
     xarray
-# new matplotlib dependency
-python -m pip install --upgrade contourpy
 # to limit the runtime of Upstream CI
 python -m pip install \
     -i https://pypi.anaconda.org/scipy-wheels-nightly/simple \