remove mamba before conda env adaption

Author: mjohnson541

deps/build.jl

@@ -2,10 +2,10 @@ using PyCall
 if PyCall.pyversion.major != 3 || PyCall.pyversion.minor != 7
     using Conda
     const Pkg = Base.require(Base.PkgId(Base.UUID("44cfe95a-1eb2-52ea-b672-e2afdf69b78f"), "Pkg"))
-
+    Conda.rm("mamba")
     Conda.add("conda=4")
     Conda.add("python=3.7")
-    
+    Conda.add("mamba")
     try
         Conda.rm("numpy") #get around MKL problem
     catch e