conda error. install via pip/pypi as build chain was doing before

Author: neontty

.travis.yml

@@ -16,7 +16,7 @@ env:
     - DISTRIB="conda" PYTHON_VERSION="3.7"
       NUMPY_VERSION="1.15.3" SCIPY_VERSION="1.2.1" CYTHON_VERSION="0.28.5"
     - DISTRIB="conda" PYTHON_VERSION="3.5" COVERAGE="true"
-      NUMPY_VERSION="1.10.4" SCIPY_VERSION="0.17.0" CYTHON_VERSION="0.23.5" SCIKIT_LEARN_VERSION="0.22.1"
+      NUMPY_VERSION="1.10.4" SCIPY_VERSION="0.17.0" CYTHON_VERSION="0.23.5" SCIKIT_LEARN_VERSION="0.22.2.post1"
 
 install: source ci_scripts/install.sh
 script: bash ci_scripts/test.sh

ci_scripts/install.sh

@@ -24,15 +24,16 @@ popd
 
 # Configure the conda environment and put it in the path using the
 # provided versions
-SCIKIT_LEARN_ARG=""
-if [[ ! -z $SCIKIT_LEARN_VERSION ]]; then
-    SCIKIT_LEARN_ARG="scikit-learn=$SCIKIT_LEARN_VERSION"
-fi
 conda create -n testenv --yes python=$PYTHON_VERSION pip nose \
-      numpy=$NUMPY_VERSION scipy=$SCIPY_VERSION cython=$CYTHON_VERSION $SCIKIT_LEARN_ARG matplotlib pandas networkx
+      numpy=$NUMPY_VERSION scipy=$SCIPY_VERSION cython=$CYTHON_VERSION matplotlib pandas networkx
 
 source activate testenv
 
+if [[ ! -z $SCIKIT_LEARN_VERSION ]]; then
+    #can't install via conda due to a package conflict, but we have been
+    # allowing pip to install to this env during our dependency process.
+    pip install scikit-learn==$SCIKIT_LEARN_VERSION
+fi
 
 if [[ "$COVERAGE" == "true" ]]; then
     pip install coverage coveralls