Upgrade sbt-verify to 0.4.1

Also drop the errors in favour of warnings for just a bit better
developer experience.

Author: Christos KK Loverdos

.circleci/Dockerfile

@@ -28,6 +28,6 @@ WORKDIR /home/circleci
 USER circleci
 
 RUN \
-  git clone https://github.com/input-output-hk/sbt-verify.git &&\
+  git clone --branch v0.4.1 --depth=1 https://github.com/input-output-hk/sbt-verify.git &&\
   cd sbt-verify &&\
   sbt publishLocal

.circleci/config.yml

@@ -4,7 +4,7 @@ jobs:
     environment:
       - SBT: "sbt -v -mem 1024"
     docker:
-      - image: rtkaczyk/mantis-circleci:v4
+      - image: rtkaczyk/mantis-circleci:v6
     steps:
       - checkout
 

build.sbt

@@ -171,8 +171,8 @@ val root = project.in(file("."))
         includeScala = true,
         includeDependency = true,
         excludedJars = Nil,
-        warnOnUnverifiedFiles = false,
-        warnOnUnusedVerifications = false
+        warnOnUnverifiedFiles = true,
+        warnOnUnusedVerifications = true
       ),
       dist in Universal := ((dist in Universal) dependsOn verify).value
     )

project/plugins.sbt

@@ -4,7 +4,7 @@ addSbtPlugin("org.scoverage" %% "sbt-coveralls" % "1.1.0")
 addSbtPlugin("org.scalastyle" %% "scalastyle-sbt-plugin" % "0.8.0")
 addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % "1.0.6")
 addSbtPlugin("com.thoughtworks.sbt-api-mappings" % "sbt-api-mappings" % "latest.release")
-addSbtPlugin("uk.co.josephearl" % "sbt-verify" % "0.3.0-SNAPSHOT")
+addSbtPlugin("uk.co.josephearl" % "sbt-verify" % "0.4.1")
 addSbtPlugin("com.thesamet" % "sbt-protoc" % "0.99.12")
 
 libraryDependencies += "com.trueaccord.scalapb" %% "compilerplugin" % "0.6.6"