Improve Clang-IWYU to automatically make #include fixes (#9858)

Co-authored-by: Mehrdad <noreply@github.com>

.github/workflows/main.yml

@@ -18,7 +18,7 @@ jobs:
         # Useful info: https://help.github.com/en/articles/workflow-syntax-for-github-actions
         include:
           - name: ubuntu
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             python-version: 3.6
           - name: windows-msvc
             os: windows-2019
@@ -99,9 +99,4 @@ jobs:
       continue-on-error: true
       if: runner.os == 'Linux'
       shell: bash -e -o pipefail -l {0}
-      run: |
-        sudo apt-get install -qq -o=Dpkg::Use-Pty=0 iwyu
-        bazel build \
-          --keep_going \
-          --config=iwyu \
-          "//:*"
+      run: ci/travis/iwyu.sh process "//:*"