CI: Fix miniconda upgrade issues

Author: Tom Augspurger

ci/setup_env.sh

@@ -41,9 +41,12 @@ else
   exit 1
 fi
 
-wget -q "https://repo.continuum.io/miniconda/Miniconda3-latest-$CONDA_OS.sh" -O miniconda.sh
-chmod +x miniconda.sh
-./miniconda.sh -b
+# wget -q "https://repo.continuum.io/miniconda/Miniconda3-latest-$CONDA_OS.sh" -O miniconda.sh
+wget -q "https://repo.anconda.com/pkgs/misc/conda-execs/conda-latest-$CONDA_OS.exe" -O conda.exe
+export CONDA_ALWAYS_YES=1
+chmod +x conda.exe
+
+./conda.exe create -p $MINICONDA_DIR python=3.7 conda
 
 export PATH=$MINICONDA_DIR/bin:$PATH