CHORE: Update cf version to use master branch

NB when the fork is pulled back into aehrc/VariantSpark, the Repo value
will need "bhosking" changed to "aehrc", and ideally the version
changed from "master" to an actual tag on the master branch.

Author: bhosking

cloud/aws-emr/cf-templates/VariantSpark_Hail_EMR_Notebook.yaml

@@ -5,7 +5,7 @@ Mappings:
   Constants:
     GitHub:
       Repo: "https://github.com/bhosking/VariantSpark"
-      Version: "bootstrap-vcs"
+      Version: "master"
 Parameters:
   # Hardware Group
   MasterNodePricing:

cloud/aws-emr/cf-templates/VariantSpark_Hail_EMR_Step.yaml

@@ -5,7 +5,7 @@ Mappings:
   Constants:
     GitHub:
       Repo: "https://github.com/bhosking/VariantSpark"
-      Version: "bootstrap-vcs"
+      Version: "master"
 Parameters:
   # Random-Forest Parameters Group
   NumTree: