chore(ci): Update header-checker-lint.yml (#46)

Author: averikitsch

.github/header-checker-lint.yml

@@ -1,15 +1,21 @@
-{"allowedCopyrightHolders": ["Google LLC"],
- "allowedLicenses": ["Apache-2.0", "MIT", "BSD-3"],
- "ignoreFiles": ["**/requirements.txt", "**/requirements-test.txt", "**/__init__.py", "samples/**/constraints.txt", "samples/**/constraints-test.txt", "docs/state_of_the_union.txt"],
- "sourceFileExtensions": [
- 	"ts", 
- 	"js", 
- 	"java", 
- 	"sh", 
- 	"Dockerfile", 
- 	"yaml", 
- 	"py",
- 	"html",
- 	"txt"
- ]
-}
+allowedCopyrightHolders:
+  - "Google LLC"
+allowedLicenses:
+  - "Apache-2.0"
+sourceFileExtensions:
+  - "yaml"
+  - "yml"
+  - "sh"
+  - "proto"
+  - "Dockerfile"
+  - "py"
+  - "html"
+  - "text"
+ignoreFiles:
+  - ".github/release-please.yml"
+  - ".github/release-trigger.yml"
+  - ".github/header-checker-lint.yml"
+  - ".github/sync-repo-settings.yaml"
+  - ".kokoro/**"
+  - "**/requirements.txt"
+  - "**/requirements-test.txt"