Revert "Update travis config to build MkDocs documentation automatically"

This reverts commit 7467e61

Author: Hironsan

.travis.yml

@@ -1,19 +1,11 @@
 language: minimal
 
-python: "3.6"
-
 services:
   - docker
 
-install:
-  - pip install mkdocs mkdocs-material
-
 script:
   - docker build --target=builder .
 
-before_deploy:
-    - mkdocs build --verbose --clean
-
 deploy:
   - provider: script
     script: tools/cd.sh travis-${TRAVIS_BUILD_NUMBER}
@@ -24,10 +16,3 @@ deploy:
     script: tools/cd.sh ${TRAVIS_TAG}
     on:
       tags: true
-
-  - provider: pages
-    skip_cleanup: true
-    github_token: $GITHUB_TOKEN
-    local_dir: site
-    on:
-        branch: master