use pip requirements in conda env, and pin reproject because of failure

Author: adrn

environment.yml

@@ -4,16 +4,7 @@ channels:
   - astropy
 
 dependencies:
-  - python=3.6
-  - IPython=6.1.0
-  - astropy=3
-  - astroquery>=0.3.7
-  - matplotlib==3.0.2
-  - numpy=1.14
-  - scipy=1.0 # needed for coordinates cross-matching
-  - jupyter=1.0
-  - notebook>=5.7.2
-  - aplpy # used in FITS-cube tutorial
-  - spectral-cube # used in FITS-cube tutorial
-  - reproject # used in FITS-cube tutorial
-  - dust_extinction>=0.7
+  - python=3.7
+  - pip
+  - pip:
+    - -r pip-requirements.txt

pip-requirements.txt

@@ -8,7 +8,7 @@ scipy>=1.0
 notebook>=5.7.2
 aplpy
 spectral-cube
-reproject
+reproject==0.5.1
 dust_extinction>=0.7
 astro-gala
 dust_extinction>=0.7