component/nghttp2: Version up

Enforce python3 usage, as the newer version requires python3.

component/nghttp2/buildout.cfg

 [buildout]
 extends =
+  ../defaults.cfg
   ../automake/buildout.cfg
   ../libtool/buildout.cfg
   ../pkgconfig/buildout.cfg
@@ -10,11 +11,12 @@ parts =
 [nghttp2]
 recipe = slapos.recipe.cmmi
 shared = true
-url = https://github.com/nghttp2/nghttp2/archive/v1.40.0.tar.gz
-md5sum = ef3c6983e0de2f16b523460c812fe598
+url = https://github.com/nghttp2/nghttp2/releases/download/v1.57.0/nghttp2-1.57.0.tar.xz
+md5sum = 1525d4966622500f119017dc057c76c8
 pre-configure =
   autoreconf -fisv -I ${libtool:location}/share/aclocal -I ${pkgconfig:location}/share/aclocal
   automake
   autoconf
 environment =
-  PATH=${autoconf:location}/bin:${automake:location}/bin:${libtool:location}/bin:${m4:location}/bin:%(PATH)s
+  PATH=${autoconf:location}/bin:${automake:location}/bin:${libtool:location}/bin:${m4:location}/bin:${xz-utils:location}/bin:%(PATH)s
+  PYTHON=${python3:executable}