Bump up version number to 1.39.2, LT revision to 32:0:18

nghttp2 v1.39.1

nghttp2 v1.39.0

nghttp2 v1.38.0

nghttp2 v1.37.0

nghttp2 v1.36.0

nghttp2 v1.35.1

nghttp2 v1.35.0

nghttp2 v1.34.0

nghttp2 v1.33.0