Fix fleet package generation (#1296)

* Fix fleet package generation
* Add .lstrip()
* Lint fix
* Add newline

detection_rules/packaging.py

@@ -471,9 +471,9 @@ class Package(object):
         manifest_file = package_dir / 'manifest.yml'
         readme_file = docs_dir / 'README.md'
         notice_file = package_dir / 'NOTICE.txt'
-        logo_file = package_dir / 'img' / 'security-logo-color-64px.png'
+        logo_file = package_dir / 'img' / 'security-logo-color-64px.svg'
 
-        manifest_file.write_text(yaml.safe_dump(manifest.asdict()))
+        manifest_file.write_text(yaml.safe_dump(manifest.to_dict()))
 
         logo_file.parent.mkdir(parents=True)
         shutil.copyfile(FLEET_PKG_LOGO, logo_file)
@@ -485,7 +485,7 @@ class Package(object):
 
         notice_contents = Path(NOTICE_FILE).read_text()
         readme_text = textwrap.dedent("""
-        # Detection rules
+        # Prebuilt Security Detection Rules
 
         The detection rules package stores the prebuilt security rules for the Elastic Security [detection engine](https://www.elastic.co/guide/en/security/7.13/detection-engine-overview.html).
 
@@ -495,7 +495,7 @@ class Package(object):
 
         ## License Notice
 
-        """) + textwrap.indent(notice_contents, prefix="    ")  # noqa: E501
+        """).lstrip() + textwrap.indent(notice_contents, prefix="    ")  # noqa: E501
 
         readme_file.write_text(readme_text)
         notice_file.write_text(notice_contents)

detection_rules/schemas/registry_package.py

@@ -5,17 +5,15 @@
 
 """Definitions for packages destined for the registry."""
 
-from dataclasses import dataclass, field
-from typing import Dict, List, Optional, Type
-
-from marshmallow import Schema
-from marshmallow_dataclass import class_schema
+from dataclasses import dataclass
+from typing import Dict, List, Optional
 
 from .definitions import ConditionSemVer, SemVer
+from ..mixins import MarshmallowDataclassMixin
 
 
 @dataclass
-class RegistryPackageManifest:
+class RegistryPackageManifest(MarshmallowDataclassMixin):
     """Base class for registry packages."""
 
     categories: List[str]
@@ -32,16 +30,5 @@ class RegistryPackageManifest:
     version: SemVer
 
     internal: Optional[bool] = None
-    policy_templates: list = field(default_factory=list)
-    screenshots: list = field(default_factory=list)
-
-    @classmethod
-    def get_schema(cls) -> Type[Schema]:
-        return class_schema(cls)
-
-    @classmethod
-    def from_dict(cls, obj: dict) -> 'RegistryPackageManifest':
-        return cls.get_schema()().load(obj)
-
-    def asdict(self) -> dict:
-        return self.get_schema()().dump(self)
+    policy_templates: Optional[list] = None
+    screenshots: Optional[list] = None