Fix doc build

.travis.yml

@@ -14,7 +14,6 @@ cache:
   - target/release/build
 install:
 - pip install 'travis-cargo<0.2' --user
-- pip install 'ghp-import' --user
 - export PATH=$HOME/.local/bin:$PATH
 addons:
   apt:
@@ -28,15 +27,10 @@ before_script:
 script:
 - travis-cargo build
 - travis-cargo test
-after_success: |
-  travis-cargo --only nightly bench &&
-  travis-cargo --only stable coveralls --no-sudo &&
-  [ $TRAVIS_BRANCH = master ] &&
-  [ $TRAVIS_PULL_REQUEST = false ] &&
-  [ $TRAVIS_RUST_VERSION = stable ] &&
-  cargo doc --no-deps &&
-  cd target/doc && git init &&
-  git push -fq https://${TOKEN}@github.com/lettre/lettre.github.io.git master
+after_success:
+- travis-cargo --only nightly bench
+- travis-cargo --only stable coveralls --no-sudo
+- travis-cargo --only stable doc-upload
 env:
   global:
-    secure: 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
+    secure: "MaZ3TzuaAHuxmxQkfJdqRfkh7/ieScJRk0T/2yjysZhDMTYyRmp5wh/zkfW1ADuG0uc4Pqsxrsh1J9SVO7O0U5NJA8NKZi/pgiL+FHh0g4YtlHxy2xmFNB5am3Kyc+E7B4XylwTbA9S8ublVM0nvX7yX/a5fbwEUInVk2bA8fpc="