chore: rename yml to yaml

Also run formatting on all yaml files.

.github/workflows/lint.yml → .github/workflows/lint.yaml

@@ -1,14 +1,14 @@
 ---
-name: 'lint'
+name: "lint"
 
 # yamllint disable-line rule:truthy
 on:
   pull_request:
     branches:
-      - '*'
+      - "*"
   push:
     branches:
-      - 'master'
+      - "master"
 
 jobs:
   hadolint:
@@ -31,8 +31,8 @@ jobs:
         uses: avto-dev/markdown-lint@04d43ee9191307b50935a753da3b775ab695eceb
         # v1.5.0 => 04d43ee9191307b50935a753da3b775ab695eceb
         with:
-          config: '.github/linters/.markdown-lint.yml'
-          args: './README.md'
+          config: ".github/linters/.markdown-lint.yaml"
+          args: "./README.md"
 
   shellcheck:
     name: shellcheck
@@ -71,4 +71,4 @@ jobs:
         uses: ibiqlik/action-yamllint@2576378a8e339169678f9939646ee3ee325e845c
         # v3.0.2 => c19bd0523a9011c3a3960fe6640a0882b59af15d
         with:
-          config_file: '.github/linters/.yamllint.yml'
+          config_file: ".github/linters/.yamllint.yaml"