Put conda and conda-build back in environment.

Author: boll3

singularity_container/environment.yml

@@ -28,6 +28,8 @@ dependencies:
   - cffi=1.14.4
   - chardet=4.0.0
   - chrpath=0.16
+  - conda=4.8.4
+  - conda-build=3.20.3
   - click=7.1.2
   - coloredlogs=15.0
   - colormath=3.0.0