nghttp2: switch to release tarball

Switch from git to xz release tarball as there's no good reason to keep
using git when release tarballs are provided.

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

package/libs/nghttp2/Makefile

@@ -3,13 +3,11 @@ include $(TOPDIR)/rules.mk
 PKG_NAME:=nghttp2
 PKG_VERSION:=1.27.0
 PKG_RELEASE:=1
-PKG_SOURCE_URL:=https://github.com/nghttp2/nghttp2.git
-PKG_SOURCE_PROTO:=git
-PKG_SOURCE_VERSION:=e8907a073f451df11952664518b9abcc3c57e65e
-PKG_SOURCE_DIR:=$(PKG_NAME)
-PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
-PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
-PKG_MIRROR_HASH:=94ece79959ca2ca2936f4e67868704c44cc377bded2e9aa25d7517ab1c7d7cbc
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
+
+PKG_SOURCE_URL:=https://github.com/nghttp2/nghttp2/releases/download/v$(PKG_VERSION)
+PKG_HASH:=e83819560952a3dc3c8d96c46f60745408f46f5f384168c90b9e3dfa53b2c2c8
+
 PKG_LICENSE:=MIT
 PKG_LICENSE_FILES:=COPYING
 CMAKE_INSTALL:=1