Add missing input for swift generated header (#1451)

Remote Build without the Bytes and/or Remote Execution doesn't work otherwise.

Risk Level: Low.
Testing: Unit tests.

Signed-off-by: Brentley Jones <brentleyjones@lyft.com>
Signed-off-by: JP Simard <jp@jpsim.com>

mobile/bazel/swift_static_framework.bzl

@@ -61,6 +61,7 @@ def _swift_static_framework_impl(ctx):
  ]
 
  if len(objc_headers) == 1:
+ input_modules_docs.append(objc_headers[0])
  zip_args.append(_zip_header_arg(module_name, objc_headers[0]))
  else:
  header_names = [header.basename for header in objc_headers]