fix: restore inclusion of header files in sdist

Changes in theacodes#80 excluded the header files needed to build on target.

Resolves theacodes#84

Signed-off-by: Mike Fiedler <[email protected]>

Author: miketheman

MANIFEST.in

@@ -2,7 +2,7 @@
 include tests/*.py
 
 # Include all third_party and generated sources needed to build cmark.
-# Note: src/cmarkgfm/*.h files are automatically included via include-package-data
+include src/cmarkgfm/*.h
 recursive-include third_party/cmark/src *.c *.h *.inc
 recursive-include third_party/cmark/extensions *.c *.h *.inc
 recursive-include generated *.h