Fix the build in Travis

.travis.yml

@@ -11,6 +11,7 @@ script:
   - sbt ++$TRAVIS_SCALA_VERSION --warn update compile scripted make-site
 
 sudo: false
+dist: trusty
 
 addons:
   apt:
@@ -23,9 +24,9 @@ before_install:
 
 install:
   - gem install jekyll:2.5.3 nanoc:3.8.0 asciidoctor --no-rdoc --no-ri
-  - npm install -g gitbook-cli
+  - npm install -g gitbook-cli@2.3.0
   - |
-    mkdir $TRAVIS_BUILD_DIR/download && mkdir $HOME/bin && \
+    mkdir $TRAVIS_BUILD_DIR/download && \
     wget https://github.com/spf13/hugo/releases/download/v0.20.1/hugo_0.20.1_linux-64bit.tar.gz -O $TRAVIS_BUILD_DIR/download/hugo.tgz && \
     tar xvf $TRAVIS_BUILD_DIR/download/hugo.tgz && \
     mv $TRAVIS_BUILD_DIR/hugo_0.20.1_linux_amd64/hugo_0.20.1_linux_amd64 $HOME/bin/hugo && \

src/sbt-test/gitbook/can-use-gitbook/build.sbt

@@ -2,12 +2,11 @@ name := "test"
 
 val checkContent = taskKey[Unit]("checkContent")
 
-val v2 = project.configure(gitbookProject("v2"))
-val v2Output = project.configure(gitbookProject("v2-output"))
+val v3Output = project.configure(gitbookProject("v3-output"))
 val v3 = project.configure(gitbookProject("v3"))
 
 val root = project.in(file("."))
-  .aggregate(v2, v2Output, v3)
+  .aggregate(v3Output, v3)
 
 def gitbookProject(version: String)(project: Project): Project = project
   .in(file(version))

src/sbt-test/gitbook/can-use-gitbook/v2-output/src/gitbook/book.json → src/sbt-test/gitbook/can-use-gitbook/v3-output/src/gitbook/book.json

@@ -1,4 +1,4 @@
 {
-  "gitbook": "2.x.x",
+  "gitbook": "3.0.3",
   "output": "target/site/docs"
 }