[doc] Support doc only release

.travis.yml

@@ -18,13 +18,14 @@ stages:
   - name: build
     if: tag IS blank
   - name: publish
-    if: tag IS present AND type != pull_request
+    if: tag IS present AND type != pull_request AND commit_message !~ /^\[doc/
   - name: release
-    if: tag IS present
+    if: tag IS present AND commit_message !~ /^\[doc/
 
 jobs:
   include:
     - stage: build
+      if: commit_message !~ /^\[doc/
       env: PROJECT=code-format
       jdk: openjdk8
       script: ./scalafmt --test
@@ -47,12 +48,13 @@ jobs:
         - if [ "$TRAVIS_BRANCH" == "master" -a "$TRAVIS_PULL_REQUEST" == "false" ]; then
           cd $TRAVIS_BUILD_DIR && ./sbt docs/publishMicrosite; fi
     - stage: build
-      if: tag IS blank AND branch = master AND type != pull_request
+      if: tag IS blank AND branch = master AND type != pull_request AND commit_message !~ /^\[doc/
       env: PROJECT=publish
       jdk: openjdk8
       script:
         - cd $TRAVIS_BUILD_DIR && ./scripts/publish.sh
     - stage: build
+      if: commit_message !~ /^\[doc/
       env: SCALA_VERSION=2.12.8 PROJECT=projectJVM
       jdk: openjdk8
       services: postgresql
@@ -61,17 +63,19 @@ jobs:
         - ./sbt ++$SCALA_VERSION "; coverage; ${PROJECT}/test; coverageReport"
         - "./sbt coverageAggregate && bash <(curl -s https://codecov.io/bash)"
     - stage: build
+      if: commit_message !~ /^\[doc/
       env: SCALA_VERSION=2.13.0 PROJECT=projectJVM2_13
       jdk: openjdk11
       services: postgresql
       before_script: psql -c 'create database travis_ci_test;' -U postgres
       script: ./sbt ++$SCALA_VERSION "${PROJECT}/test"
     - stage: build
+      if: commit_message !~ /^\[doc/
       env: SCALA_VERSION=2.12.8 PROJECT=projectJS
       jdk: openjdk8  # Scala.js 0.6.27 didn't work with jdk11
       script: ./sbt ++$SCALA_VERSION ${PROJECT}/test
     - stage: build
-      if: tag IS blank AND branch = master AND type != pull_request
+      if: tag IS blank AND branch = master AND type != pull_request AND commit_message !~ /^\[doc/
       env: SCALA_VERSION=2.11.12 PROJECT=projectJVM
       # Build Scala 2.11 support only for master and releases
       jdk: openjdk8