Revert "chore: dont run travis for docs updates"

.travis.yml

@@ -3,7 +3,7 @@ dist: bionic
 sudo: true
 
 git:
-  depth: 2
+  depth: 1
 
 cache:
   - pip
@@ -70,16 +70,6 @@ matrix:
     env: TEST=easy_install
     script: sudo python $TRAVIS_BUILD_DIR/install.py --user travis --run-travis --production --verbose
 
-before_install:
-- |
-    if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then
-      TRAVIS_COMMIT_RANGE="FETCH_HEAD...$TRAVIS_BRANCH"
-    fi
-    git diff --name-only $TRAVIS_COMMIT_RANGE | grep -qvE '\.md$|^docs' || {
-      echo "Only docs were updated, stopping build process."
-      exit
-    }
-
 install:
   - pip install urllib3 pyOpenSSL ndg-httpsclient pyasn1