bump resolver to lts-10.3, simplify stack.yaml

stack.yaml

@@ -1,35 +1,6 @@
-# For more information, see: http://docs.haskellstack.org/en/stable/yaml_configuration.html
+resolver: lts-10.3
 
-# Specifies the GHC version and set of packages available (e.g., lts-3.5, nightly-2015-09-21, ghc-7.10.2)
-resolver: nightly-2017-12-05
-
-# Local packages, usually specified by relative directory name
 packages:
 - '.'
 
-# Packages to be pulled from upstream that are not in the resolver (e.g., acme-missiles-0.3)
 extra-deps: []
-
-# Override default flag values for local packages and extra-deps
-flags: {}
-
-# Extra package databases containing global packages
-extra-package-dbs: []
-
-# Control whether we use the GHC we find on the path
-# system-ghc: true
-
-# Require a specific version of stack, using version ranges
-# require-stack-version: -any # Default
-# require-stack-version: >= 1.0.0
-
-# Override the architecture used by stack, especially useful on Windows
-# arch: i386
-# arch: x86_64
-
-# Extra directories used by stack for building
-# extra-include-dirs: [/path/to/dir]
-# extra-lib-dirs: [/path/to/dir]
-
-# Allow a newer minor version of GHC than the snapshot specifies
-# compiler-check: newer-minor