Updated activate line for *nix

Author: jmwright

appveyor.yml

@@ -29,7 +29,7 @@ install:
     - sh: conda init bash
     - conda env create -f environment.yml
     - cmd: conda activate cadquery
-    - sh: conda activate cadquery
+    - sh: activate cadquery
     - pip install git+https://github.com/CadQuery/[email protected]
 
 build: false