feat(prettier): add YAML support (#239)

Prettier 1.14.0 adds YAML support.
(https://prettier.io/blog/2018/07/29/1.14.0.html)

.mergify.yml

@@ -7,4 +7,4 @@ rules:
         required_approving_review_count: 1
       required_status_checks:
         contexts:
-        - continuous-integration/travis-ci
+          - continuous-integration/travis-ci

.travis.yml

@@ -10,9 +10,7 @@ cache:
 
 before_install:
   # `npm ci` is available since npm@5.7.0
-  - if ruby -e "exit(1) if Gem::Version.new(ARGV[0]) >= Gem::Version.new('5.7.0')" $(npm -v); then
-      npm i -g npm@latest;
-    fi
+  - if ruby -e "exit(1) if Gem::Version.new(ARGV[0]) >= Gem::Version.new('5.7.0')" $(npm -v); then npm i -g npm@latest; fi
 
 before_script:
   - commitlint-travis

package.json

@@ -68,6 +68,10 @@
         "prettier --write",
         "markdownlint",
         "git add"
+      ],
+      "*.{yml,yaml}": [
+        "prettier --write",
+        "git add"
       ]
     },
     "ignore": [

sideci.yml

@@ -2,5 +2,5 @@ linter:
   eslint:
     npm_install: true
     options:
-      ignore-path: '.gitignore'
-      ext: '.js,.jsx,.mjs'
+      ignore-path: ".gitignore"
+      ext: ".js,.jsx,.mjs"

test/fixtures/package-empty_expected.json

@@ -23,6 +23,10 @@
         "prettier --write",
         "markdownlint",
         "git add"
+      ],
+      "*.{yml,yaml}": [
+        "prettier --write",
+        "git add"
       ]
     },
     "ignore": [

test/fixtures/package-normal_expected.json

@@ -24,6 +24,10 @@
         "prettier --write",
         "markdownlint",
         "git add"
+      ],
+      "*.{yml,yaml}": [
+        "prettier --write",
+        "git add"
       ]
     },
     "ignore": [