Add 'launch' to sets of launch file extensions (#518)

Signed-off-by: Christophe Bedard <[email protected]>

Author: christophebedard

launch_xml/launch_xml/parser.py

@@ -39,4 +39,4 @@ def load(
     @classmethod
     def get_file_extensions(cls) -> Set[Text]:
         """Return the set of file extensions known to this parser."""
-        return {'launch.xml', 'xml'}
+        return {'launch.xml', 'xml', 'launch'}

launch_yaml/launch_yaml/parser.py

@@ -57,4 +57,4 @@ def load(
     @classmethod
     def get_file_extensions(cls) -> Set[Text]:
         """Return the set of file extensions known to this parser."""
-        return {'launch.yaml', 'launch.yml', 'yaml', 'yml'}
+        return {'launch.yaml', 'launch.yml', 'yaml', 'yml', 'launch'}