use python3.8, skip it rmgmolecule or rmg are installed

Author: mjohnson541

deps/build.jl

@@ -1,22 +1,16 @@
 using PyCall
-if PyCall.pyversion.major != 3 || PyCall.pyversion.minor != 7
-    using Conda
+using Conda
+packages = Conda._installed_packages()
+if !("rmg" in packages) && !("rmgmolecule" in packages) && (PyCall.pyversion.major != 3 || PyCall.pyversion.minor != 8)
     const Pkg = Base.require(Base.PkgId(Base.UUID("44cfe95a-1eb2-52ea-b672-e2afdf69b78f"), "Pkg"))
-    Conda.rm("mamba")
-    Conda.add("conda=4")
-    Conda.add("mamba")
-    Conda.update()
-    Conda.add("python=3.7")
+    Conda.add("python=3.8")
     try
         Conda.rm("numpy") #get around MKL problem
     catch e 
     end
     Conda.add("nomkl")
     Conda.add("numpy")
-    packages = Conda._installed_packages()
-    if !("rmg" in packages) && !("rmgmolecule" in packages) #if rmg and rmgmolecule not present install molecule
-        Conda.add_channel("hwpang")
-        Conda.add("rmgmolecule")
-    end
+    Conda.add_channel("hwpang")
+    Conda.add("rmgmolecule")
     Pkg.build("PyCall")
 end