update scala build toolchain (openlawteam#125)

* update scala build toolchain

* add infra to codeowners for toolchain versions

.github/CODEOWNERS

@@ -0,0 +1,3 @@
+# Toolchain and dependency upgrades must be reviewed for infra
+build.sbt   @openlawteam/infra
+project/*   @openlawteam/infra

Dockerfile

@@ -1,7 +1,7 @@
 # The scala-builder stage compiles Openlaw.scala into JavaScript output,
 # via the ScalaJS stuff. There are some other sbt dependencies that also
 # get bundled up into the output, including openlaw-core.
-FROM openlaw/scala-builder:node as builder
+FROM openlaw/scala-builder:0.10.0-node as builder
 # 1. install plugins and dependencies.
 # 
 # we do this in two different stages to take advantage of layer caching, with

build.sbt

@@ -2,7 +2,15 @@ import scala.language.postfixOps
 
 licenses += ("Apache-2.0", url("https://opensource.org/licenses/Apache-2.0"))
 
-lazy val scalaV = "2.12.8"
+/*
+The Scala and SBT versions must be matched to the version of scala-builder used
+as the base image of the container. We try to standardize across projects and
+always upgrade in a controlled fashion.
+
+If you wish to update either Scala or SBT, please open an issue and and tag
+@openlawteam/infra.
+*/
+lazy val scalaV = "2.12.10"
 
 lazy val repositories = Seq(
   Resolver.jcenterRepo,

project/build.properties

@@ -1 +1,7 @@
+# The Scala and SBT versions must be matched to the version of scala-builder
+# used as the base image of the container. We try to standardize across projects
+# and always upgrade in a controlled fashion.
+#
+# If you wish to update either Scala or SBT, please open an issue and and tag
+# @openlawteam/infra.
 sbt.version=1.2.8