Fix PyLint: Consider explicitly re-raising

platformio/platform/board.py

@@ -28,8 +28,8 @@ class PlatformBoardConfig(object):
         self.manifest_path = manifest_path
         try:
             self._manifest = fs.load_json(manifest_path)
-        except ValueError:
-            raise InvalidBoardManifest(manifest_path)
+        except ValueError as exc:
+            raise InvalidBoardManifest(manifest_path) from exc
         if not set(["name", "url", "vendor"]) <= set(self._manifest):
             raise UserSideException(
                 "Please specify name, url and vendor fields for " + manifest_path

platformio/platform/factory.py

@@ -35,8 +35,8 @@ class PlatformFactory(object):
         sys.modules["platformio.managers.platform"] = base
         try:
             return load_python_module("platformio.platform.%s" % name, path)
-        except ImportError:
-            raise UnknownPlatform(name)
+        except ImportError as exc:
+            raise UnknownPlatform(name) from exc
 
     @classmethod
     def new(cls, pkg_or_spec, autoinstall=False) -> base.PlatformBase: